enable timber for debug

Author: Manabu-GT

app/src/main/java/com/ms_square/android/design/overlay/app/DesignOverlayApplication.java

@@ -3,14 +3,22 @@
 import android.app.Application;
 import android.preference.PreferenceManager;
 
+import com.ms_square.android.design.overlay.BuildConfig;
 import com.ms_square.android.design.overlay.R;
 
+import timber.log.Timber;
+
 public class DesignOverlayApplication extends Application {
 
     @Override
     public void onCreate() {
         super.onCreate();
 
+        if (BuildConfig.DEBUG) {
+            // set up Timber for logging
+            Timber.plant(new Timber.DebugTree());
+        }
+
         // set default values for the app preference
         PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
     }