Add documentation for contributing to federation development

docs/src/SUMMARY.md

@@ -13,6 +13,7 @@
 - [Contributing](contributing.md)
   - [Docker Development](contributing_docker_development.md)
   - [Local Development](contributing_local_development.md)
+  - [Federation Development](contributing_federation_development.md)
   - [Websocket/HTTP API](contributing_websocket_http_api.md)
   - [ActivityPub API Outline](contributing_apub_api_outline.md)
   - [Theming Guide](contributing_theming.md)

docs/src/contributing_federation_development.md

@@ -0,0 +1,37 @@
+# Federation Development
+
+## Setup
+
+If you don't have a local clone of the Lemmy repo yet, just run the following command:
+
+```bash
+git clone https://yerbamate.dev/nutomic/lemmy.git -b federation
+```
+
+If you already have the Lemmy repo cloned, you need to add a new remote:
+```bash
+git remote add federation https://yerbamate.dev/nutomic/lemmy.git
+git checkout federation
+git pull federation federation
+```
+
+## Running
+
+You need to have the following packages installed, the Docker service needs to be running.
+
+- docker
+- docker-compose
+- cargo
+- yarn
+
+Then run the following
+```bash
+cd dev/federation-test
+./run-federation-test.bash
+```
+
+After the build is finished and the docker-compose setup is running, open [127.0.0.1:8540](http://127.0.0.1:8540) and
+[127.0.0.1:8541](http://127.0.0.1:8541) in your browser to use the test instances. You can login as admin with
+username `lemmy` and password `lemmy`, or create new accounts.
+
+Please get in touch if you want to contribute to this, so we can coordinate things and avoid duplicate work.