added more docu

Add more Documentation on how to run the backend app

README.md

 # Chaos Parcel Serivce: Backend
 
+The backend is a simple FastAPI app (https://fastapi.tiangolo.com/) usign a sqlite database
+
+
+## Development
+To test and develop, you can run it on your computer.  
+
+check the repo out and change your workign directory into the top level
+
+create a virtual env
+```
+python -m venv venv
+```
+
+activate the virtual env
+```
+. venv/bin/activate
+```
+
+install required dependencies
+```
+pip install -r requirements.txt
+pip install -r requirements-dev.txt
+```
+
+for development, use the uvicorn server
+```
+pip install uvicorn
+```
+
+now you can run the app
+```
+uvicorn backend.main:app --reload
+```
+
+It will use the default setting from backend/config.py  
+you can override settings using a .env file in the working directory
+
+
 ## Deployment
-This assumes you run the code as user *www-data*  
-Do **not** checkout this code as the same user.  
+This assumes you run the code as user *www-data* and the code is checked out at /srv/backend
+Do **not** checkout this code as the user ruining the code. the **onyl** requried writeable location is the database directory/file
+
 checkout the code (main branch for production)  
 cd into the directory  
 
@@ -48,8 +87,13 @@ create a runtime directory to allow the webserver to forward calls to
 mdkir /run/bgp
 chown www-data:www-data /run/bgp
 ```
+on production systems you may want to create a /etc/tmpfiles.d/bgp_backend.conf
+```
+d   /run/bgp/   0750 www-data www-data - -
+```
+to create the file on boot
 
-create a systemd service file to serve the app:
+create a systemd service file to serve the app in /etc/systemd/system/bgp_backend.service:
 ```
 [Unit]
 Description=Gunicorn instance to serve bgp backend fastapi app
@@ -64,3 +108,15 @@ ExecStart=/srv/backend/venv/bin/gunicorn -k uvicorn.workers.UvicornWorker --bind
 [Install]
 WantedBy=multi-user.target
 ```
+
+now you can run the app
+```
+systemctl daemon-reload
+systemctl start bgp_backend
+```
+
+in your webserver use the socket at /run/bgp/socket to connect the webserver to the app  
+on nginx the backend url would look like this:
+```
+unix:/run/bgp/socket
+```