build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext.kotlin_version = '1.2.31'
    repositories {
        jcenter()
        google()
        maven {
            url  "https://dl.bintray.com/android/android-tools"
        }
        maven {
            url "https://maven.google.com"
        }

    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:3.2.1'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
        google()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}