Add 'bcrypt-ruby' gem for password encryption

Signed-off-by: Marvin Khristian Zamora <marvinlz@ph.ncs-i.com>
Add user db migration artifacts

Signed-off-by: Marvin Khristian Zamora <marvinlz@ph.ncs-i.com>
Implement user model

The new model uses the "has_secure_password"
rails flag that automatically handles password validation

Signed-off-by: Marvin Khristian Zamora <marvinlz@ph.ncs-i.com>
Merge branch 'feature/modeling-users' into next