Adding form of grade creation and controller grades and action create grade
 Issue #434 resources controller and routes
 Issue #434 resources views
 Issue #434 resources action new
 Issue #434 add top side bar
 Issue #434 action new routes
#447 added add_problems action in contests controller
#447 added initial view for add problems page
#447 view fixes, now name and description show correctly
 Issue #434 models modification
 Issue #434 views modification
 Issue #434 controller modification
#447 added routes
#447 added add action in contests controller
#447 bug fixes, added functionality of adding problems
#447 added documentation and removed unnecessary instance variable
#447 removed unnecessary comment
Issue #433, generalizing validate method and building a general rspec test
Issue #433, updating validate script for all types of problems in addition to documentation
Issue #433, Adding logic of assignment problem in script