Issue #73 Adds notification migrations
Fix errors in notification migrations
Issue #73 Add IdeaNotification, UserNotification models and update assosiations with User and Idea models
Issue #73 renamed UserNotificaiton model
Issue #73 Add Notification models inheriting from IdeaNotification and UserNotification
Issue #73 Add send and text methods to VoteNotification model
Issue #73 Add send and text methods to CommentNotification model
Issue #73 Add send and text methods to DeleteNotification model
Issue #73 Add send and text methods to EditNotification model
Issue #73 Add send and text methods to ArchiveNotification model
Issue #73 Add send and text methods to DisapproveTdeaNotification model
Issue #73 Fix error in some notification models

in DeleteNotification, EditNotification, ArchiveNotification, DisapproveIdeaNotification line 4 changed from CommentNotification.new to (Action)Notification.new
Issue #73 Add send and text methods to InviteCommitteeNotification model
Issue #73 Add send and text methods to ApproveCommitteeNotification model
Issue #73 Rename IdeaNotification model
Issue #73 Change parameters of send method in IdeaNotifications
Issue #73 Rename table user_notifications_users
Merge branch 'C1_AminaZoheir_#73_Notifications_migrations' into C1_AminaZoheir_#73_Notification_Module
Issue #73 Fix some errors in notification models

1. Add missing .save at the enf os send_notification method
2. Correct class names
 Issue #73 Addsociations