Collaborative editing (#1660)

docs/SERVICES.md

@@ -0,0 +1,45 @@
+# Backend Services
+
+Outline's backend is split into several distinct [services](../server/services)
+that combined form the application. When running the official Docker container
+it will run all of the production services by default.
+
+You can choose which services to run through either a comma separated CLI flag,
+`--services`, or the `SERVICES` environment variable. For example:
+
+```bash
+yarn start --services=web,worker
+```
+
+## Admin
+
+Currently this service is only used in development to view and debug the queues.
+It is hosted at `/admin`.
+
+## Web
+
+The web server hosts the Application and API, as such this is the main service
+and must be run by at least one process.
+
+## Websockets
+
+The websocket server is used to communicate with the frontend, it can be ran on
+the same box as the web server or separately.
+
+## Worker
+
+At least one worker process is required to process the [queues](../server/queues).
+
+## Collaboration
+
+The service is in alpha and as such is not started by default. It must run
+separately to the `websockets` service, and will not start in the same process.
+The `COLLABORATION_URL` must be set to the publicly accessible URL when running
+the service. For example, if the app is hosted at `https://docs.example.com` you
+may use something like: `COLLABORATION_URL=wss://docs-collaboration.example.com`.
+
+Start the service with:
+
+```bash
+yarn start --services=collaboration
+```