Fix undefined repository test in ViewModel constructor

Fix this test that failed.

describe('ViewModel', function() {

  describe('creating a ViewModel', function() {

    describe('without repository', function() {

      it('it should throw an error', function() {

        expect(function() {
          new ViewModel({ data: 'other stuff' });
        }).to.throwError();

      });

    }); ….
Merge pull request #4 from nubizsoft/master

Fix undefined repository test in ViewModel constructor