Merge pull request #453 from DamavandiKamali/master

The function call was deprecated

README.md

@@ -63,7 +63,7 @@ Php::Value my_plus(Php::Parameters &params)
 The method call to export the above C++ function:
 
 ```c
-extension.add("my_plus", my_plus, {
+extension.add<my_plus>("my_plus", {
     Php::ByVal("a", Php::numericType),
     Php::ByVal("b", Php::numericType)
 });