Add docs about usage with Ionic

[theunreal]

Anyone managed to run this plugin with Ionic and can share the steps?

[IvanLjubicic]

I also didnt manage to get it to work yet. Keep getting this error

Ad failed to load : 0

[uKioops]

Hi i'm using ionic/angular/capacitor. I followed the step shown to install and get it to work. But you'll see the ad only after adding capacitor and loading with android studio (and modifiying the manifest etc...) on a device. You can't show ad in the "Ionic serve".

To know : banner ad overlap your view (there is some fixes in the issues page)