add Google Plus in About section

app/src/main/java/com/simplemobiletools/calculator/activities/AboutActivity.java

@@ -72,4 +72,10 @@ public class AboutActivity extends AppCompatActivity {
         }
         startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(link)));
     }
+
+    @OnClick(R.id.about_gplus)
+    public void googlePlusClicked() {
+        final String link = "https://plus.google.com/communities/104880861558693868382";
+        startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(link)));
+    }
 }

app/src/main/res/layout/activity_about.xml

@@ -55,6 +55,15 @@
         android:layout_below="@+id/about_follow_us"
         android:src="@mipmap/facebook"/>
 
+    <ImageView
+        android:id="@+id/about_gplus"
+        android:layout_width="@dimen/social_logo"
+        android:layout_height="@dimen/social_logo"
+        android:layout_below="@+id/about_follow_us"
+        android:layout_marginLeft="@dimen/social_padding"
+        android:layout_toRightOf="@+id/about_facebook"
+        android:src="@mipmap/gplus"/>
+
     <TextView
         android:id="@+id/about_version"
         android:layout_width="match_parent"