Make rollback more informative

[m-darbinyan]

Closes #45

Description

This PR improves the rollback process by making it more informative. The key improvements include:

• Adds a message before each rollback indicating the gem is rolling back a phantom migration.
• Displays the error message if something goes wrong during the rollback.
• Prints a success message when all rollbacks are completed successfully.
• Updates the error summary to list the failed migrations with their filename and branch, and adds some steps on how to fix them. Error messages have been removed from the summary as they are now displayed during the rollback process.

Screenshots

Success

Before	After

Error

Before	After

[ka8725]

Thanks for your contribution!