Guide start-hello in Russian
small fixes
guide WIP [skip ci]
improved HTML guide navigation
Fix .gitignore for `basic` and `advanced` application templates
improve cache phpdoc
Merge pull request #3763 from creocoder/yii2-applications-gitignore-fix

Fix .gitignore for `basic` and `advanced` application templates
edited installation guide
edited "hello" guide
Excess \yii\base\Model::resolveFields() method removed
Merge pull request #3764 from creocoder/excess-model-methods

Excess \yii\base\Model::resolveFields() method removed
\yii\i18n\DbMessageSource code style fixes
Merge pull request #3769 from creocoder/db-message-source-code-style-fix

\yii\i18n\DbMessageSource code style fixes
file validator added mime - types , image validator fixed
file validator tests added
Merge pull request #3762 from MUTOgen/guide-start-forms

Russian guide. Start forms
Merge pull request #3773 from Ragazzo/file_validator_adjusted

File validator adjusted
ensure guide PDF compiles with russian characters
fixed note about search class
Merge pull request #3775 from Ragazzo/widgets_guide_adjusted

fixed note about search class