Enables the search to evaluate more than one discipline for a student.
Merge branch 'master' of https://github.com/Datenbankpraktikum2013/Datenvisualisierung

Conflicts:
	app/models/search.rb
Merges search object
Merge branch 'master' of https://github.com/Datenbankpraktikum2013/Datenvisualisierung