How to add `plugins` block to android `build.gradle` file

Hi

I’m working on OneSignal integration for Fuse, In order for this integration to be complete i need to add the following code at the beginning of build.gradle file

plugins {id 'com.onesignal.androidsdk.onesignal-gradle-plugin' version '0.8.1'}

apply plugin: 'com.onesignal.androidsdk.onesignal-gradle-plugin'

I’m not able to find anything useful on Fuse Documentation of Forums

I checked all Fuse documentation and didn’t found a way to do it

did i miss something ? is there any way to do it ?