Document config file format and options

README.md

@@ -66,3 +66,83 @@ in the full version you want to install:
 ```bash
 $ cargo install --force --git https://github.com/Garmelon/cove --tag v0.1.0
 ```
+
+## Config file
+
+Cove's config file uses the [TOML](https://toml.io/) format.
+
+When launched, cove prints the location it is loading its config file from. To
+configure cove, create a config file at that location. This location can be
+changed via the `--config` command line option.
+
+The following is a complete list of available options. If a command line option
+with the same purpose exists, it takes precedence over the option specified in
+the config file.
+
+### `data_dir`
+
+**Type:** String (representing path)  
+**Default:** Platform dependent
+
+The directory that cove stores its data in when not running in ephemeral mode.
+
+Relative paths are interpreted relative to the user's home directory.
+
+See also the `--data-dir` command line option.
+
+### `ephemeral`
+
+**Type:** Boolean  
+**Default:** `false`
+
+Whether to start in ephemeral mode.
+
+In ephemeral mode, cove doesn't store any data. It completely ignores any
+options related to the data dir.
+
+See also the `--ephemeral` command line option.
+
+### `offline`
+
+**Type:** Boolean  
+**Default:** `false`
+
+Whether to start in offline mode.
+
+In offline mode, cove won't automatically join rooms marked via the `autojoin`
+option on startup. You can still join those rooms manually by pressing `a` in
+the rooms list.
+
+See also the `--offline` command line option.
+
+### `euph.rooms.<room>.autojoin`
+
+**Type:** Boolean  
+**Default:** `false`
+
+Whether to automatically join this room on startup.
+
+### `euph.rooms.<room>.username`
+
+**Type:** String  
+**Default:** Not st
+
+If set, cove will set this username upon joining if there is no username
+associated with the current session.
+
+### `euph.rooms.<room>.force_username`
+
+**Type:** Boolean  
+**Default:** `false`
+
+If `euph.rooms.<room>.username` is set, this will force cove to set the username
+even if there is already a different username associated with the current
+session.
+
+### `euph.rooms.<room>.password`
+
+**Type:** String  
+**Default:** Not st
+
+If set, cove will try once to use this password to authenticate, should the room
+be password-protected.