[ 'request' => [ // !!! insert a secret key in the following (if it is empty) - this is required by cookie validation 'cookieValidationKey' => '' ] ] ]; if (! YII_ENV_TEST) { // configuration adjustments for 'dev' environment $config ['bootstrap'] [] = 'debug'; $config ['modules'] ['debug'] = 'yii\debug\Module'; $config ['bootstrap'] [] = 'gii'; $config ['modules'] ['gii'] = 'yii\gii\Module'; } return $config;