Exception when editing a user to not be a member of the current roster anymore.

[werebus]

If you're editing a user from the "Roster A" route (e.g. if Roster A has an id of 1, '/rosters/1/users/5). And you don't include "Roster A" in the list of selected rosters, then you get an exception here:

screaming-dinosaur/app/controllers/users_controller.rb

Lines 85 to 86 in 334b3ba

	membership = @user.membership_in @roster
	return true if membership.update membership_params

Because, at that point, the user has already been updated to not be in that roster anymore, so @user.membership_in @roster is nil

Note that the intended action — removing the user from "Roster A" — is successful in this case. But the user gets a 500.