Appledash: Rotten to the core

(WARNING MATURE AUDIENCES ONLY) After Rainbow Dash finds out about Fluttershy and Applejack´s relationship, she is heartbroken, because she has a crush on Applejack. So she makes up a plan to ruin their relationship, and so that she can get what she really wants. She uses the chance at her pet turtle Tank´s birthday party, for her malicious scheme. What is she up to? and what will happen next?