What is Like-Gating?
Suppose you want, a user can play your app only if he/she has liked your page.
You can Like-gate your app. i.e user can not play your app without liking your page
How to Like-Gate your app?
We have made separate website for like-gating http://likekaro.com
All steps have been explained in the website
Just remember 'destination url' will be your app's link