Adds Carer and Senior models.
Adds Account, Carer and Senior models. Adds migrations to create Accounts table. Adds migration to include type attribute in Users table.
Adds updated schema.rb generated by rake db:migrate
Adds account_id foreign key to Users table
Merge pull request #5 from gabrieltaylor/feature/3-aos-and-tcs-should-be-able-to-log-in

Adds Account, Carer and Senior models (with associations). Adds migrations to create Accounts table. Adds migration to include type attribute in Users table. Adds account_id foreign key to Users table.