your_first_app V2

add  introduce App/description of controller
Revert "your_first_app V2"

This reverts commit f0e402e87393bf7773347a6c99d23383aa8d3893.
Revert "Revert "your_first_app V2""

This reverts commit 3fa2ecac5b03a32beb26352cfee6ce357a18a879.