Issue #192 - Add regId and deviceType in the session model
Fix a typo in the offer model documentation
Add PendingInvitation and InvitationMessage model
Add missing lines to models
Add migration for session , pendingInvitation and invitationMessage
Test the models
Merge pull request #199 from ndomar/Database-Models

Database_Add migration for session , pendingInvitation and invitationMessage
Issue #163 - Add email field and making inviteeId nullable
Merge pull request #200 from ndomar/Database-Models

Database_Add emain in Pending invitation and make inviteeId nullable
Merge branch 'develop' of https://github.com/ndomar/megasoft-14 into C2_EslaMaged_#3_Register
Issue #161 - A user can register via providing an email, username, bio and password