Modify you metadata file with new column name that you are going to add/modify. For example i have a user table metadata file and want to add a phone column. The metadata file is in yml format. Metadata files are found under the following path
lets open the file that you want to modify and add the following lines:
phone: type: string nullable: true length: 255 options: fixed: false
Now Run the following doctrine command to update your Entity class based on the changes at your metadata file. Here i am updating only my Users Entity Class.
php bin/console doctrine:generate:entities AppBundle:Users
Now run the following doctrine command to update your database table with the modification you have done yet.
php bin/console doctrine:schema:update --force