Make GSR Group Admin easy to add/remove users

[vcai122]

For easy adding/removing users to groups

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 90.41%. Comparing base (4f18580) to head (ed8bf40).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
backend/gsr_booking/admin.py	75.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #307      +/-   ##
==========================================
- Coverage   90.47%   90.41%   -0.06%     
==========================================
  Files          62       62              
  Lines        2666     2681      +15     
==========================================
+ Hits         2412     2424      +12     
- Misses        254      257       +3     

Flag	Coverage Δ
	90.41% <75.00%> (-0.06%)	⬇️

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[dr-Jess]

lgtm