owncloud : LDAP intergration apps is missing

First clone the app into owncloud apps-folder, mostly /home/XXX/public_html/owncloud/app

1. sudo git clone https://github.com/owncloud/user_ldap.git 
2. /home/XXX/public_html/owncloud/occ app:enable user_ldap 

Source:

• https://central.owncloud.org/t/ldap-user-and-group-backend-app-is-missing-oc-10-0/7261/32 
• https://doc.owncloud.org/server/10.0/admin_manual/configuration/server/occ_command.html