When there is a 'postgresql schema' issue, add a workable command.

\*Is your feature request related to a problem? Please describe.\*A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]기능 요청이 특정 문제에 연관된 것이라면 여기에 그 문제를 설명해주세요.

when error occurred below command, I don't know what to do to fix the error.command: `./backend.ai mgr start-server --debug`

\*Describe the solution you'd like\*A clear and concise description of what you want to happen.어떤 기능이 있으면 좋겠는지 자세히 설명해주세요.

show any command like `./py -m alembic upgrade head` when database schema error.

\*Describe alternatives you've considered\*A clear and concise description of any alternative solutions or features you've considered.혹시 다른 대안들을 생각해본 적이 있다면 함께 적어주세요.

auto update database schema whenever start manager server

\*Additional context\*Add any other context or screenshots about the feature request here.기능 요청에 대해 보다 잘 이해할 수 있는 다른 맥락을 기술해주세요.

After installing 'backend.ai', an error occurred when running the Manager component.

I found out that I needed to update the field with the help of the person next to me, but I probably wouldn't have solved it without help.

JIRA Issue: BA-258