Add structure-extensions.md to translate into Russian
First pass of edits
structure-extensions.md is translated to Russian
Added more notes and a book reference to testing intro
Replaced Amazon link with ISBN
Adjusted testing namespaces in application templates
Added description to each test config of advanced application
Added faker to basic app console commands, adjusted readme to mention database setup
fixes for translation of file 'structure-extensions.md' to Russian
fixes for translation of file 'structure-extensions.md' to Russian
Merge branch 'master' of https://github.com/maxmirazh33/yii2
Merge branch 'master' of git://github.com/yiisoft/yii2
more doc [skip ci]
Fix PHPDoc
Unused InvalidConfigException
Merge pull request #4807 from mrarthur/patch-6

Unused InvalidConfigException
fixes typos in start-databases.md
Merge pull request #4808 from nenad-zivkovic/master

fixes typos in start-databases.md
Merge pull request #4806 from mrarthur/patch-5

Fix PHPDoc
Merge pull request #4804 from maxmirazh33/master

structure-extensions.md translated to Russian[skip-ci]