Park Mi-sun

Ho Goo-hee, a high schooler and self-proclaimed pushover, discovers a new application on her phone that offers to take revenge on anyone whose name she writes in it. (wikipedia)

The story of the relationship between two families, based on the traditional Korean Cinderella folktale about Kongji and Patji. The Kongji family is poor but kind, while the Patji family is rich but selfish. (imdb)