https://github.com/githubjeka/yii2-tutorial
http://www.yiiframework.com/doc-2.0/guide-index.html
https://nix-tips.ru/yii2-api-guides/
http://rutor.biz/2016/08/12/frejmvork-yii2-s-nulya-do-profi-polnyj-videokurs-2016-pcrec/
https://yii2-cookbook.readthedocs.io/
http://codeception.com/for/yii
http://codeception.com/docs/modules/Yii2
http://codeception.com/docs/01-Introduction
https://www.youtube.com/playlist?list=PLyFjBjJZlCruF_3D080zEYw2biMMRKKJ_