Move custom libs to the source tree

libs/SimpleValidator/Validators/Numeric.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace SimpleValidator\Validators;
+
+class Numeric extends Base
+{
+    public function execute(array $data)
+    {
+        if ($this->isFieldNotEmpty($data)) {
+            return is_numeric($data[$this->field]);
+        }
+
+        return true;
+    }
+}