Added unique key to user_name field to support addition of login via user name.
Added unique key to user_name field to support addition of login via user name.

focuz07/CRM,bradgearon/ChurchCRM,focuz07/CRM,focuz07/CRM,focuz07/CRM,bradgearon/ChurchCRM,ChurchCRM/CRM,bradgearon/ChurchCRM,ChurchCRM/CRM,ChurchCRM/CRM,ChurchCRM/CRM,ChurchCRM/CRM,bradgearon/ChurchCRM,bradgearon/ChurchCRM