ME: added a cases insensitive checker and a failing test case for it
ME: added functionality to check username is unique and case insensitive
ME: solved flake8 issues
ME: added username validation in user_profile_serilizer.py
ME: added organization name validation in organization_serilizer.py
ME: corrected flake8 errors and removed unwanted code
ME: added request method checker; lack of this checker failed 'test_partial_updates' test case
ME: remove blank line flake8 was complaining about