added template for user defined class File

- a constructor which takes a human readable name and the file
      and internally stores the contents of the file
    - if the file does not exist, then file_get_contents function
      returns false, in that case the contents of the file is an empty
      string

lib/codegen/php/curl.dart

@@ -58,6 +58,29 @@ curl_setopt(\$request, {{method}}, 1);
 curl_close(\$request);
 var_dump(\$response);
 
+""";
+
+  String kFileClassString = """
+class File
+{
+    public string \$name;
+    public string \$filename;
+    public string \$content;
+
+    function __construct(\$name, \$filename)
+    {
+        \$this->name = \$name;
+        \$this->filename = \$filename;
+        \$available_content = file_get_contents(\$this->filename);
+        \$this->content = \$available_content ? \$available_content : "";
+    }
+}
+
+
+""";
+
+}
+
 """;