Description of problem:
Internal error 500 is returned when you try adding a system to the same group twice (i.e. if you don't notice it's already there).
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. add system to group (admin->groups->[some group])
2. try to add it one more time
internal server error
error message saying the operation could not be finished as the system is already a member of that group.
on gerrit: http://gerrit.beaker-project.org/1789
Verified, was greeted with error.
System 'system.example.com' is already in group 'admin'
Beaker 0.12 has been released.