Subject -> page association
Merge commit '32d22a495f8649db19677a4258deeef7d409c443' into One_to_oneAssociation

* commit '32d22a495f8649db19677a4258deeef7d409c443':
  Gem addition: yaml_db; For db to seed
Merge branch 'One_to_oneAssociation'

* One_to_oneAssociation:
  Subject -> page association