add jbuilder dep
fix enrollments plurality in HelpRequests model
add position method
add compound index to enrollments
Fix error in enrollments fixture student reference
add untested implementations of help request endpoints
add views for help request endpoints
update views to use help_request partial
add created_at, extra instances for help_requests fixtures
test help_requests endpoints
Merge pull request #17 from cs198/help-requests

Help requests endpoints