fix: updated DB-scheme. feat: DB-communication works for assessment.

...c/main/java/unipotsdam/gf/interfaces/IPeerAssessment.java

...essment/controller/service/AssessmentDBCommunication.java

.../modules/assessment/controller/service/FBAssessement.java

...modules/assessment/controller/service/PeerAssessment.java

...es/assessment/controller/service/PeerAssessmentDummy.java

...tsdam/gf/modules/assessment/controller/view/QuizView.java

...nsamforschen/src/main/webapp/assets/js/finalAssessment.js

...samforschen/src/main/webapp/assets/js/rateContribution.js

gemeinsamforschen/src/main/webapp/assets/js/takeQuiz.js

gemeinsamforschen/src/main/webapp/pages/rateContribution.jsp

gemeinsamforschen/src/scripts/dbschema/fltrail.sql