doc(readme): make the README remotely useful

README.md

@@ -1,17 +1,42 @@
 # oeffimaster
 
-A new Flutter project.
+Aggregating information to create your own routes in public transit effortlessly.
 
-## Getting Started
 
-This project is a starting point for a Flutter application.
+## Goal of this project
+Do you ever get a route from google maps and see a 13 minute switch time, for a train that comes every ten minutes? Do you then prompt another app with better results. What if you'd normally have to wait 9 minutes for your train, but the previous train is late, so in reality you can switch with only a minutes worth of waiting? Now you can get an earlier train for the next connection, and suddenly the 3rd-fastest connection in google's algorithm becomes the fastest, and you saved 10 minutes - or could have, if you knew.
+My app will not solve this issue.
+As someone who is familiar with good chunks of the cities public transport network, I often enough *think* I can get faster to my target than the routing served by commonplace apps, but I have a hard time of knowing that for sure. Other apps allow some degree of comparing routes to one another, but it's not a priority, and editing any part of it is not supported at all.
+Oeffimaster aims to make that type of information easily accessible and aggregate it in the most helpful way, allowing comparison and editing of routes.
 
-A few resources to get you started if this is your first Flutter project:
+## Usage
+I am currently providing artifacts for linux and android. To make your own builds, you will need an api key for your network.
 
-- [Learn Flutter](https://docs.flutter.dev/get-started/learn-flutter)
+## Build the project
-- [Write your first Flutter app](https://docs.flutter.dev/get-started/codelab)
-- [Flutter learning resources](https://docs.flutter.dev/reference/learning-resources)
 
-For help getting started with Flutter development, view the
+### Get the API key
-[online documentation](https://docs.flutter.dev/), which offers tutorials,
+For the VBB network in Berlin/Brandenburg
-samples, guidance on mobile development, and a full API reference.
+
+1. Installing flutter: https://docs.flutter.dev/install/quick
+2. Get an API key for VBB: https://unternehmen.vbb.de/digitale-services/api/
+    It will take some time, but they will send you an API key and the url to access it.
+    this should work for other public transit networks using the HAFAS api, but you will have to test this yourself
+
+### The build part
+Create a `.env` in the project root and add
+```env
+VBB_API_KEY=
+VBB_API_URL=
+```
+For local builds and connected devices simply run `flutter run` in your terminal.
+
+To build for linux:
+```bash
+flutter build linux -DVBB_API_KEY={API_KEY} -DVBB_API_URL={API_URL}
+
+```
+
+To build for android:
+```
+flutter build apk -DVBB_API_KEY={API_KEY} -DVBB_API_URL={API_URL}
+```