Documentation enhancements (#73)

docs/stores/firebase.md

@@ -0,0 +1,52 @@
+# Google Firebase Identity store
+https://firebase.google.com/
+
+## Features
+|      Name      | Supported? |
+|----------------|------------|
+| Authentication | Yes        |
+| Directory      | No         |
+| Identity       | Yes        |
+
+## Requirements
+This backend requires a suitable Matrix client capable of performing Firebase authentication and passing the following
+information:
+- Firebase User ID as Matrix username
+- Firebase token as Matrix password
+
+If your client is Riot, you will need a custom version.
+
+## Configuration
+```yaml
+firebase.enabled: <boolean>
+```
+Enable/disable this identity store.
+
+Example:
+```yaml
+firebase.enabled: <boolean>
+```
+
+---
+
+```yaml
+firebase.credentials: <string>
+```
+Path to the credentials file provided by Google Firebase to use with an external app.
+
+Example:
+```yaml
+firebase.credentials: '/path/to/firebase/credentials.json'
+```
+
+---
+
+```yaml
+firebase.database: <string>
+```
+URL to your Firebase database.
+
+Example:
+```yaml
+firebase.database: 'https://my-project.firebaseio.com/'
+```