Initial data commit

Task/Singleton/PHP/singleton.php

@@ -0,0 +1,21 @@
+class Singleton {
+  protected static $instance = null;
+  public $test_var;
+  private function __construct(){
+    //Any constructor code
+  }
+  public static function getInstance(){
+    if (is_null(self::$instance)){
+      self::$instance = new self();
+    }
+    return self::$instance;
+  }
+}
+
+$foo = Singleton::getInstance();
+$foo->test_var = 'One';
+
+$bar = Singleton::getInstance();
+echo $bar->test_var; //Prints 'One'
+
+$fail = new Singleton(); //Fatal error