Don't dereference symlink in create_migration

When using a symlink to create_migration.php the script would create the migration in the script folder instead of the folder holding the symlink.

From commit:
At nitroxy-web a symlink points to the real script so the migration would be created in the script folder rather than the symlink folder.

(regression after the symlink mess last week, create_migration.php was a copy while the other were symlinks)