website/docs: add docs for websocket connections

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

website/developer-docs/setup/frontend-only-dev-environment.md

@@ -0,0 +1,51 @@
+---
+title: Frontend-only development environment
+---
+
+If you want to only make changes on the UI, you don't need a backend running from source. You can user the docker-compose install with a few customizations.
+
+### Prerequisites
+
+- Node (any recent version should work, we use 16.x to build)
+- Make (again, any recent version should work)
+- Docker and docker-compose
+
+### Instructions
+
+1. Clone the git repo from https://github.com/goauthentik/authentik
+2. In the cloned repository, follow the docker-compose installation instructions [here](/docs/installation/docker-compose)
+3. Add the following entry to your `.env` file:
+
+    ```
+    AUTHENTIK_IMAGE=beryju.org/authentik/server
+    AUTHENTIK_TAG=gh-next
+    AUTHENTIK_OUTPOSTS__DOCKER_IMAGE_BASE=beryju.org/authentik/outpost-%(type)s:gh-next
+    AUTHENTIK_LOG_LEVEL=debug
+    AUTHENTIK_WEB_LOAD_LOCAL_FILES=true
+    ```
+
+    This will cause authentik to use the beta images.
+
+4. Add this volume mapping to your compose file
+
+    ```yaml
+    version: '3.2'
+
+    services:
+      # [...]
+      server:
+        # [...]
+        volumes:
+          - ./web:/web
+          - ./local.env.yml:/local.env.yml
+    ```
+
+    This makes the local web files and the config file available to the authentik server.
+
+5. Run `docker-compose up -d` to apply those changes to your containers.
+6. `cd web`
+7. Run `npm i` and then `npm run watch` to start the build process.
+
+You can now access authentik on http://localhost:9000 (or https://localhost:9443).
+
+You might also want to complete the initial setup under `/if/flow/initial-setup/`.