Create user connected to model
Merge pull request #43 from Gruppe01/CreateUser

Create user connected to model
Merge pull request #44 from Gruppe01/persistence-updatehandler

Added loginCheck method.
added method set user (as of current user)
added login check
minor fix
disabled login check
username tag fixed
Merge pull request #45 from Gruppe01/login

Login
small fix
constructor fixes
Merge pull request #46 from Gruppe01/CreateMeeting

Create meeting
minor fix
Merge pull request #47 from Gruppe01/persistence-updatehandler

DataStorage
Changed time objects to new LocalDateTime
Merge pull request #48 from Gruppe01/model-meeting

Changed time objects to new LocalDateTime
Merge pull request #49 from Gruppe01/persistence-updatehandler

Added classes for all database entities.
Updated getElementsByID methods.