added instance variable to controller in order to render error messages correctly
removed unneeded method
removed unneeded method
added calculate percent method
added dependent destroy to deleting an assignment
changed calculation method for current percentage
changed percent calculation method for course
changed way of calculating current grade in enrollment
removed describe spec for deleted method
changed student percent calculation and added capitalization to title and category of assignment display
Merge pull request #198 from rwarbelow/fixing_bugs

Fixing bugs