Added Bcrypt to gemfile

Added current_user helper to application controller.
Added migration to add password hash/salt fields to teacher table.
Included Bcrypt in teacher model along with password encryption methods.
Added password and password confirmation fields to new teacher form partial.
Allowed for params password to be used in teacher controller.
Added password encryption fields to Students.
Added password encryption methods to Student model.
Allowed password params to be used in Student controller.
Added password and password confirmation fields to new student form partial.
Merge pull request #6 from bootcoder/student_password

Student password good job devin, really like the new current user method