Added a "GROUP BY" on the users' ID for the query fetching the students for grading on the admin/gradebook/assessments/grade page, so that users with more than one access record will only be shown once in the list.
Merge branch 'develop' of https://github.com/EntradaProject/entrada-1x into develop

# By Josh Dillon
# Via Josh Dillon
* 'develop' of https://github.com/EntradaProject/entrada-1x:
  addition to the course enrolment api, fix for javascript bug