Added tshock README

tshock/README.md

@@ -0,0 +1,29 @@
+# Build arguments
+The only required build argument is `RELEASE_TAG`. This is the GitHub tag of
+the release you wish to use. The releases can be found
+[here](https://github.com/Pryaxis/TShock/releases). The release tag is the
+identifier on the left. It should look something like  `v4.4.0-pre15`. You can
+then specify the variable in the `.env` file: e.g. `RELEASE_TAG=v4.4.0-pre15`
+
+# Environment variables
+The only provided environment variable is `AUTOCREATE`. This should be either
+`1`, `2` or `3`. It specifies how big the generated world should, e.g. small,
+medium or large. If a world file already exists, the existing file is used
+instead of generating a new one.
+
+# Mount points
+There a three useful mount points defined:
+
+* `/terraria/config`: this is where the server config files are located
+* `/terraria/logs`: the server log files are dumped here
+* `/terraria/worlds`: this is where the world files are stored
+
+You can mount these directories somewhere in the host file system by specifying
+the mount paths in the `.env` file. These can be both absolute or relative
+paths.
+
+# Other config variables
+You can specify the port using the `PORT` variable. This configures which port
+on the host system should be exposed for the Terraria server. This is also the
+port you need to enter into the Terraria client in order to connect to the
+server. The default port for Terraria servers is `7777`.