Improve ignored files. Add composer.lock file.
Configuring test suite.
Ignore IDE files.
First test green.
Setting departure time in Departure.
When not defined, arrival time is equal to departure time.
Setting arrival time.
Duration when no arrival time is defined.
Calculate duration.
Rename Departure to Trip.
Improve variable name.
Fix typo.
Arrive time must be greater or equal to departure time.
Refactor arrival time check.