Fatal error: Uncaught Error: Class "yii\db\Migration" not found in /home/tandomain/projects.codersinsight.co.tz/hrsystem/console/migrations/m180623_205625_create_course_document_table.php:8 Stack trace: #0 {main} thrown in /home/tandomain/projects.codersinsight.co.tz/hrsystem/console/migrations/m180623_205625_create_course_document_table.php on line 8