README.md: some updates

README.md

@@ -1,15 +1,12 @@
 # API-server
 Apollo server written in typescript that handles business logic.
-
+## Assumptions
+Userserver and postgres are running e.g. with Julius' Docker Compose.
 ## Usage
-### Configure Postgres
-Install postgresql and configure it, so the Database is accessible from remote hosts (only necessary for docker container [Here](https://wiki.archlinux.org/index.php/PostgreSQL))
-
-See postgres client config in __ormconfig.json__
 ### Docker
 ```bash
 docker build -t <image name> .
-docker run --rm --network="host" <image name>
+docker run --rm -p 4000:4000 <image name>
 ```
 The Dockerfile is pretty stupid and could produce a smaller image, e.g. with multistage build.
 ### Compile and run
@@ -33,3 +30,14 @@ And start gulp in watch mode
 gulp watch
 ```
 This will watch *.ts files in _./src_ and recompile to _./dist_ and finally restart the server.
+
+## Environment Variables
+The following environment variables can be used to configure the server:
+```bash
+RPC_HOST=host:port
+NODE_ENV=development/porduction
+POSTGRES_CONNECTION_URL=postgres://username:password@host:port/database_name
+```
+- __RPC_HOST__ is used for the connection with the userserver.
+- __NODE_ENV__ will not check authentication if set to development
+- __POSTGRES_CONNECTION_URL__ for connection with the postgres database