Added test for transaction support for `.addAssociation`
Added test
Added transaction support for hasMany `.addAssociation`
Merge branch 'feature/add-association-transaction-support' into feature/create-relation-objects

Conflicts:
	test/associations/has-many.test.js
Used the wrong `sequelize` in tests
Merge branch 'feature/add-association-transaction-support' into feature/create-relation-objects
Added transaction support for `.createAssociation`
Bugfix: Make sure DAO#find() takes `transaction` option in first parameter
Fix BelongsTo.getAssociation to use the bugfix as well. Removed `.only` call in tests.
Merge branch 'bugfix/find-transaction-option' into feature/create-relation-objects
Added `.createAssociation` support for `HasOne` and `BelongsTo`