Added devtools detection.

assets/js/helpers/in_array.js

@@ -0,0 +1,12 @@
+function in_array(needle, haystack) {
+    for (var i = 0; i < haystack.length; i ++) {
+        if (needle == haystack[i]) {
+            return true;
+            break;
+        }
+    }
+
+    return false;
+}
+
+export default in_array;