Add configurable adapter selection to app runner

README.md

@@ -5,12 +5,27 @@ default v2 app run:
 python3 ./youdis.py
 ```
 
+`youdis.py` is the app-level runner. It starts the backend first, waits for health, then starts each enabled adapter explicitly.
+
 direct component runs still work for testing:
 ```
 python3 -m uvicorn youdis.main:app --host 127.0.0.1 --port 8000
 python3 -m youdis.adapters.discord
 ```
 
+adapter selection is controlled by env, currently:
+```
+YOUDIS_RUN_BACKEND=1
+YOUDIS_ENABLED_ADAPTERS=discord
+```
+
+to add a new adapter:
+1. add `youdis/adapters/<adapter>.py`
+2. make it independently runnable
+3. add `start_<adapter>()` to `youdis.py`
+4. register it in the explicit adapter starter map in `youdis.py`
+5. add any required env vars to `.env.example`
+
 build and run the docker container
 ```
 DISCORD_BOT_TOKEN = [discord bot token]