If migration folder doesn't exist in phar binary

[dmouse]

When you create a phar if you don't include a migration file the folder is not included in your distribution binary, this cause an error when you run the migration command

   Symfony\Component\Finder\Exception\DirectoryNotFoundException 

  The "phar:///home/.../database/migrations" directory does not exist.

[owenvoke]

@nunomaduro, what are your thoughts on this? Seems fine to me. The alternative is just making sure that the migrations directory is in your box.json which is what I think we've previously recommended. However, this would cope with when there are no migrations but you still want to use the DB I guess?

[dmouse]

Yes, my case is I'm using the dump command to generate the SQL file with all the schema and I want to use that SQL as base and create migration files out of the phar file.

As you mention to include the migration folder in the phar file I need migrations

[NotWorkingCode]

@nunomaduro

This problem is very relevant, especially if you intentionally do not use migrations, but use an existing database.
In this case, I must create an empty folder, otherwise I will get errors that the folder does not exist.

Could you consider this PR?