build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    ext.kotlin_version = '1.1.3-2'

    repositories {
        maven { url 'https://maven.google.com' }
        maven { url 'https://maven.fabric.io/public' }
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.2'
        classpath 'com.google.gms:google-services:3.0.0'
        classpath 'com.google.firebase:firebase-plugins:1.1.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'io.fabric.tools:gradle:1.+'
    }
}

allprojects {
    repositories {
        jcenter()
        maven { url 'https://maven.google.com' }
        maven { url 'https://maven.fabric.io/public' }
        maven { url 'https://jitpack.io' }
        mavenCentral()
    }
}

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