First you would need to rollback the changes from db.
Assuming that the migration generated for Miropost
is the latest migration in your db
.
Just run
rake db:rollback ## This will drop the table miroposts
After this destroy the existing scaffold by :
rails destroy scaffold Miropost content:string user_id:integer
Then all you need to do is to recreate the scaffold with correct spelling and run rake db:migrate