implemented new storageAdapter
update composer lock
Merge pull request #12 from mariansollmann/issue-12

Refactor model: Song
Refactor "link" to new model
Merge pull request #10 from njam/issue-10

Refactor model: Link
Merge branch 'master' of github.com:denkmal/denkmal.org into issue-13

Conflicts:
	library/Denkmal/resources/db/structure.sql
Added default value, adjusted test for new create