padded readme out. made python location configurable. made ignore_bots configurable. replaced max_message_length with serenity's provided constant

README.md

@@ -11,4 +11,23 @@ Serenity and Rust are proving wonders for SoundFX. This is all in an effort to r
 ## How do I use it?
 You'll need rustc and cargo for compilation. To run, you'll need Python 3 still (due to no suitable replacement for dateparser in Rust)
 
-TODO fill out the rest of this
+### Compiling
+Reminder Bot can be built by running `cargo build --release` in the top level directory.
+
+### Setting up Python
+Reminder Bot by default looks for a venv within it's working directory to run Python out of. To set up a venv, install `python-venv` and run `python -m venv venv`. Then, run `source venv/bin/activate` to activate the venv, and do `pip install dateparser` to install the required library
+
+### Environment Variables
+Reminder Bot reads a number of environment variables. Some are essential, and others have hardcoded fallbacks. Environment variables can be loaded from a .env file in the working directory.
+
+__Required Variables__
+* `DATABASE_URL` - the URL of your MySQL database (`mysql://user[:password]@domain/database`)
+* `DISCORD_TOKEN` - your application's bot user's authorization token
+
+__Other Variables__
+* `LOCAL_TIMEZONE` - default `UTC`, necessary for calculations in the natural language processor
+* `DEFAULT_PREFIX` - default `$`, used for the default prefix on new guilds
+* `SUBSCRIPTION_ROLES` - default `None`, accepts a list of Discord role IDs that are given to subscribed users
+* `CNC_GUILD` - default `None`, accepts a single Discord guild ID for the server that the subscription roles belong to
+* `IGNORE_BOTS` - default `1`, if `1`, Reminder Bot will ignore all other bots
+* `PYTHON_LOCATION` - default `venv/bin/python3`. Can be changed if your Python executable is located somewhere else