Fix detection of teachers
include teacher changes
change timetable_changes datetime to date
Store some more timetable change data
Include a readable_day field

Returns Monday B instead of 6
changes method
Monkey patch Date to include a method to parse from an excel date
Add debugger and update other gems
rocket_pants now uses active_model_serializers
Don't give everyones timetable when querying the users list
Include the teachers full name in the teacher_name method
Merge branch 'master' into rocketpants