Merge pull request #2 from MartinOrtel/assignment4

history tabels added for being able to track changes in database
todo.txt file added which should be used for tracking task
addded users to todo.txt with low prio
todo.txt updated, task #2 added
Merge branch 'master' of https://github.com/MartinOrtel/DatenbankFoerdermittel into assignment4
Mitarbeiter has been changes to Interne
Auftragnehmer has been changes to Externe
this change is necessary after our meeting with Mr. Weist showed
that our database modell is inaccurate in regarding people associated with a Baumassnahme