Modified create account validation behavior
	- Implemented the Username duplication error.
	- Created a new backbone model for checking of usernames.

Modified the user profile api
	- Added a new route for checking of usernames.
	- Added a 404 response in the showProfile method if username is not found.
Modified create account validation behavior
Modified create account validation behavior
Modified create account validation behavior(1134)
  - Implemented the Username duplication error.
  - Created a new backbone model for checking of usernames.

Modified the user profile api
  - Added a new route for checking of usernames.
  - Added a 404 response in the showProfile method if username is not found.