Minimal Server Edition

This release contains the minimal functionality of the OBD readings server; namely,

• POST and PUT endpoint at / that accepts OBD readings from the app.
• Connection to a PostgreSQL database to store accepted readings
• /view endpoint to see all vehicleids stored in the database
• /view/<vehicleid> endpoint to (kinda) dump readings for a given vehicle ID.

Database connection is specified by the DATABASE_URL environment variable.
Port number can be specified by the PORT environment variable; otherwise, defaults to port 5000.