Install role_model and cancancan

For security features.

Signed-off-by: Joan Tiffany Siy <joan@teamcodeflux.com>
Update User model with security methods

Also compiled new attributes in one migration file.

Signed-off-by: Joan Tiffany Siy <joan@teamcodeflux.com>
Update UserController

Based on pesto implementation

Signed-off-by: Joan Tiffany Siy <joan@teamcodeflux.com>