Add javascript runtime and readline.
Allow flexible ruby version
Remove ruby version lock and update scrub_database script for rails 4
Fix view_my_scores timeout
Fix the versions controller and views.
Fix grades#view_my_scores
Fix the Revert/Impersonate side button
Optimize grades#view
Fix categories and nodes relationship
Remove failing cucumber tests

These tests should be reimplemented as the CSC517 projects are completed.
Add the rails4 branch to travis
Add tests for the student_task model
Fix the schema file for Travis
Fix associating an assignment with a course from the assignment.
Clean up due_dates in assignment#edit
Clean up assignments#edit for due_dates
Add a missing jquery plugin. Fixes due_dates in Assignments#edit
Add indices to the response_maps models
Clean up participant/response/response_maps relationships.
Destroy participant response_maps when a team is destroyed. Closes #428