Issues #412 #413 removing extra tab
Issues #415 adding assignment table
Merge pull request #427 from alaashafaee/dev_database

Dev database
Issues #415 #426 + seperating table problem into 3 tables
Issues #432 #431 #419 #418
Merge branch 'database_migrations' into dev_database

Conflicts:
	tutor/db/migrate/20140323110716_create_courses.rb
	tutor/db/migrate/20140323112245_create_problems.rb
	tutor/db/migrate/20140323112347_create_solutions.rb
	tutor/db/migrate/20140505095450_create_contests.rb