User authetication error messages

Description

Adding error handling for user authentication.

Issue

Issue 82

Feature

• Added error handling for user login and user registration

Tophatting

• The endpoints now return a an error status and error message
• Message Body Format

{
    "error_code": "LOGIN_SUCCESS",
    "error_message": "User logged in successfully"
}

Expected current behavior

• Registration Checks:
  • email, password, and username are specified
  • username is unique
  • username has length of 8-30 characters
  • valid username format: starts with alphabet (a-z, or A-Z), all other characters can be alphabets, numbers, or underscores, length of 8-30 characters
  • email verification: valid email address format by RFC 5322
  • email is unique: no user with this email exists already
  • password length verification: password must be at least 6 characters in length
• Login Checks:
  • email is specified
  • password is specified
  • user with email exists
  • check for password matching

Changes

• Added Error Codes
• Modified Message class to format error codes and error messages
• Added logic for authentication error handling

Screenshots

None

Design Patterns

List any design patterns used to accomplish this task None.

Deviations

Were there any deviations from the original design or architecture plan. If yes, what were they ? None.

Additional

• Unit test written
• Meets requirements
• Cross-browser tested
• Added/updated documentation as needed
• Camel case style used

Closes #82 (closed)