I want to give the Rails app to Heroku.

I can't tell for sure unless I look at the log, but is it probably because port 5000 is not available?Why don't you specify detached and try not to receive a response from heroku?

$herokurun:detached rakedb:migrate

Before you do the above, use another console.

$heroku logs --tail

If you monitor the log as , you will know what is going on.
After implementation,

$herokurlogs

But if you look at the log in real time, you can see it intuitively.