diff --git a/.flake8 b/.flake8
index cab8ba8..1707912 100644
--- a/.flake8
+++ b/.flake8
@@ -8,7 +8,6 @@ exclude =
     __pycache__,
     alembic,
     htmlcov,
-    tests,
     venv
 # Disable rules that we don't care about (or conflict with others)
 extend-ignore =
@@ -30,10 +29,14 @@ ignore-decorators=overrides
 max-line-length = 120
 # Disable some rules for entire files
 per-file-ignores =
-    # Missing __all__, main isn't supposed to be imported
+    # DALL000: Missing __all__, main isn't supposed to be imported
     main.py: DALL000,
-    # Missing __all__, Cogs aren't modules
+    # DALL000: Missing __all__, Cogs aren't modules
     ./didier/cogs/*: DALL000,
+    # DALL000: Missing __all__, tests aren't supposed to be imported
+    # S101: Use of assert, this is the point of tests
+    ./tests/*: DALL000 S101,
+    # D103: Missing docstring in public function
     # All of the colours methods are just oneliners to create a colour,
     # there's no point adding docstrings (function names are enough)
-    ./didier/utils/discord/colours.py: D103
+    ./didier/utils/discord/colours.py: D103,
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 6380e4b..10eabb9 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -34,6 +34,8 @@ repos:
     rev: 4.0.1
     hooks:
     -   id: flake8
+        exclude: ^(alembic|.github)
+        args: [--config, .flake8]
         additional_dependencies:
           - "flake8-bandit"
           - "flake8-bugbear"
diff --git a/alembic/versions/1716bfecf684_add_birthdays.py b/alembic/versions/1716bfecf684_add_birthdays.py
new file mode 100644
index 0000000..9065993
--- /dev/null
+++ b/alembic/versions/1716bfecf684_add_birthdays.py
@@ -0,0 +1,38 @@
+"""Add birthdays
+
+Revision ID: 1716bfecf684
+Revises: 581ae6511b98
+Create Date: 2022-07-19 21:46:42.796349
+
+"""
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "1716bfecf684"
+down_revision = "581ae6511b98"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table(
+        "birthdays",
+        sa.Column("birthday_id", sa.Integer(), nullable=False),
+        sa.Column("user_id", sa.BigInteger(), nullable=True),
+        sa.Column("birthday", sa.DateTime(), nullable=False),
+        sa.ForeignKeyConstraint(
+            ["user_id"],
+            ["users.user_id"],
+        ),
+        sa.PrimaryKeyConstraint("birthday_id"),
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table("birthdays")
+    # ### end Alembic commands ###
diff --git a/database/crud/birthdays.py b/database/crud/birthdays.py
new file mode 100644
index 0000000..99ea2db
--- /dev/null
+++ b/database/crud/birthdays.py
@@ -0,0 +1,34 @@
+from datetime import date
+from typing import Optional
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from database.crud import users
+from database.models import Birthday
+
+__all__ = ["add_birthday", "get_birthday_for_user"]
+
+
+async def add_birthday(session: AsyncSession, user_id: int, birthday: date):
+    """Add a user's birthday into the database
+
+    If already present, overwrites the existing one
+    """
+    user = await users.get_or_add(session, user_id)
+
+    if user.birthday is not None:
+        bd = user.birthday
+        await session.refresh(bd)
+        bd.birthday = birthday
+    else:
+        bd = Birthday(user_id=user_id, birthday=birthday)
+
+    session.add(bd)
+    await session.commit()
+
+
+async def get_birthday_for_user(session: AsyncSession, user_id: int) -> Optional[Birthday]:
+    """Find a user's birthday"""
+    statement = select(Birthday).where(Birthday.user_id == user_id)
+    return (await session.execute(statement)).scalar_one_or_none()
diff --git a/database/models.py b/database/models.py
index d663204..74aa5fc 100644
--- a/database/models.py
+++ b/database/models.py
@@ -12,6 +12,7 @@ Base = declarative_base()
 __all__ = [
     "Base",
     "Bank",
+    "Birthday",
     "CustomCommand",
     "CustomCommandAlias",
     "DadJoke",
@@ -46,6 +47,18 @@ class Bank(Base):
     user: User = relationship("User", uselist=False, back_populates="bank", lazy="selectin")
 
 
+class Birthday(Base):
+    """A user's birthday"""
+
+    __tablename__ = "birthdays"
+
+    birthday_id: int = Column(Integer, primary_key=True)
+    user_id: int = Column(BigInteger, ForeignKey("users.user_id"))
+    birthday: datetime = Column(DateTime, nullable=False)
+
+    user: User = relationship("User", uselist=False, back_populates="birthday", lazy="selectin")
+
+
 class CustomCommand(Base):
     """Custom commands to fill the hole Dyno couldn't"""
 
@@ -149,6 +162,9 @@ class User(Base):
     bank: Bank = relationship(
         "Bank", back_populates="user", uselist=False, lazy="selectin", cascade="all, delete-orphan"
     )
+    birthday: Optional[Birthday] = relationship(
+        "Birthday", back_populates="user", uselist=False, lazy="selectin", cascade="all, delete-orphan"
+    )
     nightly_data: NightlyData = relationship(
         "NightlyData", back_populates="user", uselist=False, lazy="selectin", cascade="all, delete-orphan"
     )
diff --git a/didier/cogs/discord.py b/didier/cogs/discord.py
new file mode 100644
index 0000000..1152922
--- /dev/null
+++ b/didier/cogs/discord.py
@@ -0,0 +1,49 @@
+import discord
+from discord.ext import commands
+
+from database.crud import birthdays
+from didier import Didier
+from didier.utils.types.datetime import str_to_date
+from didier.utils.types.string import leading
+
+
+class Discord(commands.Cog):
+    """Cog for commands related to Discord, servers, and members"""
+
+    client: Didier
+
+    def __init__(self, client: Didier):
+        self.client = client
+
+    @commands.group(name="Birthday", aliases=["Bd", "Birthdays"], case_insensitive=True, invoke_without_command=True)
+    async def birthday(self, ctx: commands.Context, user: discord.User = None):
+        """Command to check the birthday of a user"""
+        user_id = (user and user.id) or ctx.author.id
+        async with self.client.db_session as session:
+            birthday = await birthdays.get_birthday_for_user(session, user_id)
+
+        name = "Jouw" if user is None else f"{user.display_name}'s"
+
+        if birthday is None:
+            return await ctx.reply(f"{name} verjaardag zit niet in de database.", mention_author=False)
+
+        day, month = leading("0", str(birthday.birthday.day)), leading("0", str(birthday.birthday.month))
+
+        return await ctx.reply(f"{name} verjaardag staat ingesteld op **{day}/{month}**.", mention_author=False)
+
+    @birthday.command(name="Set", aliases=["Config"])
+    async def birthday_set(self, ctx: commands.Context, date_str: str):
+        """Command to set your birthday"""
+        try:
+            date = str_to_date(date_str)
+        except ValueError:
+            return await ctx.reply(f"`{date_str}` is geen geldige datum.", mention_author=False)
+
+        async with self.client.db_session as session:
+            await birthdays.add_birthday(session, ctx.author.id, date)
+            await self.client.confirm_message(ctx.message)
+
+
+async def setup(client: Didier):
+    """Load the cog"""
+    await client.add_cog(Discord(client))
diff --git a/didier/utils/types/datetime.py b/didier/utils/types/datetime.py
index 3701b4f..91c3583 100644
--- a/didier/utils/types/datetime.py
+++ b/didier/utils/types/datetime.py
@@ -1,6 +1,13 @@
-__all__ = ["int_to_weekday"]
+import datetime
+
+__all__ = ["int_to_weekday", "str_to_date"]
 
 
 def int_to_weekday(number: int) -> str:  # pragma: no cover # it's useless to write a test for this
     """Get the Dutch name of a weekday from the number"""
     return ["Maandag", "Dinsdag", "Woensdag", "Donderdag", "Vrijdag", "Zaterdag", "Zondag"][number]
+
+
+def str_to_date(date_str: str) -> datetime.date:
+    """Turn a string into a DD/MM/YYYY date"""
+    return datetime.datetime.strptime(date_str, "%d/%m/%Y").date()
diff --git a/readme.md b/readme.md
index 4fd4143..dae8347 100644
--- a/readme.md
+++ b/readme.md
@@ -42,6 +42,12 @@ docker-compose up -d db-pytest
 # Starting Didier
 python3 main.py
 
+# Running database migrations
+alembic upgrade head
+
+# Creating a new database migration
+alembic revision --autogenerate -m "Revision message here"
+
 # Running tests
 pytest
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 95b44db..8530de5 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -12,6 +12,10 @@ from didier import Didier
 
 @pytest.fixture(scope="session", autouse=True)
 def event_loop() -> Generator:
+    """Fixture to change the event loop
+
+    This fixes a lot of headaches during async tests
+    """
     loop = asyncio.get_event_loop_policy().new_event_loop()
     yield loop
     loop.close()
@@ -33,6 +37,7 @@ async def tables():
 @pytest.fixture
 async def database_session(tables) -> AsyncGenerator[AsyncSession, None]:
     """Fixture to create a session for every test
+
     Rollbacks the transaction afterwards so that the future tests start with a clean database
     """
     connection = await engine.connect()
@@ -52,6 +57,7 @@ async def database_session(tables) -> AsyncGenerator[AsyncSession, None]:
 @pytest.fixture
 def mock_client() -> Didier:
     """Fixture to get a mock Didier instance
+
     The mock uses 0 as the id
     """
     mock_client = MagicMock()
diff --git a/tests/test_database/conftest.py b/tests/test_database/conftest.py
index de1e939..8bc765c 100644
--- a/tests/test_database/conftest.py
+++ b/tests/test_database/conftest.py
@@ -3,7 +3,33 @@ import datetime
 import pytest
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from database.models import UforaAnnouncement, UforaCourse, UforaCourseAlias
+from database.crud import users
+from database.models import Bank, UforaAnnouncement, UforaCourse, UforaCourseAlias, User
+
+
+@pytest.fixture(scope="session")
+def test_user_id() -> int:
+    """User id used when creating the debug user
+
+    Fixture is useful when comparing, fetching data, ...
+    """
+    return 1
+
+
+@pytest.fixture
+async def user(database_session: AsyncSession, test_user_id) -> User:
+    """Fixture to create a user"""
+    _user = await users.get_or_add(database_session, test_user_id)
+    await database_session.refresh(_user)
+    return _user
+
+
+@pytest.fixture
+async def bank(database_session: AsyncSession, user: User) -> Bank:
+    """Fixture to fetch the test user's bank"""
+    _bank = user.bank
+    await database_session.refresh(_bank)
+    return _bank
 
 
 @pytest.fixture
diff --git a/tests/test_database/test_crud/test_birthdays.py b/tests/test_database/test_crud/test_birthdays.py
new file mode 100644
index 0000000..96b924c
--- /dev/null
+++ b/tests/test_database/test_crud/test_birthdays.py
@@ -0,0 +1,47 @@
+from datetime import datetime, timedelta
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from database.crud import birthdays as crud
+from database.models import User
+
+
+async def test_add_birthday_not_present(database_session: AsyncSession, user: User):
+    """Test setting a user's birthday when it doesn't exist yet"""
+    assert user.birthday is None
+
+    bd_date = datetime.today().date()
+    await crud.add_birthday(database_session, user.user_id, bd_date)
+    await database_session.refresh(user)
+    assert user.birthday is not None
+    assert user.birthday.birthday.date() == bd_date
+
+
+async def test_add_birthday_overwrite(database_session: AsyncSession, user: User):
+    """Test that setting a user's birthday when it already exists overwrites it"""
+    bd_date = datetime.today().date()
+    await crud.add_birthday(database_session, user.user_id, bd_date)
+    await database_session.refresh(user)
+    assert user.birthday is not None
+
+    new_bd_date = bd_date + timedelta(weeks=1)
+    await crud.add_birthday(database_session, user.user_id, new_bd_date)
+    await database_session.refresh(user)
+    assert user.birthday.birthday.date() == new_bd_date
+
+
+async def test_get_birthday_exists(database_session: AsyncSession, user: User):
+    """Test getting a user's birthday when it exists"""
+    bd_date = datetime.today().date()
+    await crud.add_birthday(database_session, user.user_id, bd_date)
+    await database_session.refresh(user)
+
+    bd = await crud.get_birthday_for_user(database_session, user.user_id)
+    assert bd is not None
+    assert bd.birthday.date() == bd_date
+
+
+async def test_get_birthday_not_exists(database_session: AsyncSession, user: User):
+    """Test getting a user's birthday when it doesn't exist"""
+    bd = await crud.get_birthday_for_user(database_session, user.user_id)
+    assert bd is None
diff --git a/tests/test_database/test_crud/test_currency.py b/tests/test_database/test_crud/test_currency.py
index f996bf9..1f0a163 100644
--- a/tests/test_database/test_crud/test_currency.py
+++ b/tests/test_database/test_crud/test_currency.py
@@ -6,16 +6,6 @@ from database.exceptions import currency as exceptions
 from database.models import Bank
 
 
-DEBUG_USER_ID = 1
-
-
-@pytest.fixture
-async def bank(database_session: AsyncSession) -> Bank:
-    _bank = await crud.get_bank(database_session, DEBUG_USER_ID)
-    await database_session.refresh(_bank)
-    return _bank
-
-
 async def test_add_dinks(database_session: AsyncSession, bank: Bank):
     """Test adding dinks to an account"""
     assert bank.dinks == 0
diff --git a/tests/test_database/test_crud/test_ufora_announcements.py b/tests/test_database/test_crud/test_ufora_announcements.py
index b2385a2..4e6fc47 100644
--- a/tests/test_database/test_crud/test_ufora_announcements.py
+++ b/tests/test_database/test_crud/test_ufora_announcements.py
@@ -1,6 +1,5 @@
 import datetime
 
-import pytest
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from database.crud import ufora_announcements as crud
diff --git a/tests/test_didier/test_utils/test_discord/test_converters/test_numbers.py b/tests/test_didier/test_utils/test_discord/test_converters/test_numbers.py
index ed88692..75ab401 100644
--- a/tests/test_didier/test_utils/test_discord/test_converters/test_numbers.py
+++ b/tests/test_didier/test_utils/test_discord/test_converters/test_numbers.py
@@ -44,6 +44,7 @@ def test_abbreviated_no_number():
 
 def test_abbreviated_float_floors():
     """Test abbreviated_number for a float that is longer than the unit
+
     Example:
         5.3k is 5300, but 5.3001k is 5300.1
     """