adds spec_helper
adds initialize and all methods to Station
adds save method, needs ==
adds station == method
adds .all method to line
adds save and == methods to Line
adds id component to save methods for Station and Line
adds add_line method to Station, needs list_stations method to pass Rspec
adds ability to list all stations for a particular line
adds ability to list all lines that stop at a certain station
adds improvements and license to README