[Assignments] Ability to assign list of users to a specific assignment through API or UI

[Fergus-Wood]

Problem statement:

I have a number of assignments that are *not* assigned to "Everyone" and I need to manually add specific users into that assignment. Currently the only way to do this is manually, user-by-user for each assignment. When dealing with 100's of users, this is not scalable or feasible to do manually.

Proposed solution:

Add and API PUT method that accepts a list of user ids, and an assignment ID and adds those user to the assignment. Similarly, a DELETE method might be needed to selectively remove users from an assignment. Alternatively, the ability to paste in a LIST of users in to the "Assign" section of an assignment. Currently i can only paste a user one by one.

User role(s):

admin,instructor