whoami under the same user that you run mix tasks will give you the username, then sudo chown -R username:username /home/ubuntu/documents/blackbook to make this user (and their group) own the project root and all dirs / files recusrsively
whoami under the same user that you run mix tasks will give you the username, then sudo chown -R username:username /home/ubuntu/documents/blackbook to make this user (and their group) own the project root and all dirs / files recusrsively