Move custom libs to the source tree

libs/SimpleValidator/Validators/Integer.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace SimpleValidator\Validators;
+
+class Integer extends Base
+{
+    public function execute(array $data)
+    {
+        if ($this->isFieldNotEmpty($data)) {
+            if (is_string($data[$this->field])) {
+
+                if ($data[$this->field][0] === '-') {
+                    return ctype_digit(substr($data[$this->field], 1));
+                }
+
+                return ctype_digit($data[$this->field]);
+            }
+            else {
+                return is_int($data[$this->field]);
+            }
+        }
+
+        return true;
+    }
+}