added roles migration, model and spec files
added guardian profiles migration, model and spec files
added guardianships migration, model and spec files
added teacher profiles migration, model and spec files
added student profiles migration, model and spec files
added models for teacher, guardian and student roles
updated db schema
updated user_identity migration, model and spec validations
removed file becuase of naming conflict
added file back to match folder naming convention
Merge pull request #9 from rwarbelow/user_roles

User role migrations models and specs have been added