Create Login/Logout Functionality

[KyleBibler]

• [ ] Verify the compare password method in the User model works.
• [ ] Create a controller and view that login the User with those credentials.
  • Create a controller that uses the compare password method.
  • Create a view that has a form for the login.
  • Upon successful login, create a session for the current User.
  • Upon unsuccessful login, display helpful error messages.
• [ ] Verify the session created for the User on login works as intended.
  • Test a page that requires unexpired User session.
  • OPTIONAL: Allow functionality for Admin users with the session.
• [ ] Create a controller for logging out a User.
  • Create a button or route that maps to the logout controller.
  • Verify session variables are cleaned up/destroyed on logout.