Add EH code.

build.gradle

@@ -10,6 +10,9 @@ buildscript {
         classpath 'com.github.ben-manes:gradle-versions-plugin:0.13.0'
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
+
+        //Firebase (EH)
+        classpath 'com.google.gms:google-services:3.0.0'
     }
 }