add edit requirement feature
update requirement form layout
change requirements integration tests to pending
add delete requirement
Merge pull request #2 from asteward/requirements

Requirements
Merge front_end to master
add grade model and associations
update user model submission association
Merge pull request #3 from asteward/grades

Grades
create tabs for each assessment that display requirements and a submission form
merge grades with master
Merge branch 'master' of https://github.com/asteward/epissessments

merge grades with master
Fix assessment tab display error
update root pages based on user role
pull in changes
Merge branch 'master' of https://github.com/asteward/epissessments

Update root redirects
Add timestamps to submissions table
allow students to re-submit a submission
Add assessment requirements to student show page
Add submission requirement grades to student show page