title: Upload file using wt
body: <p>I am new to WT, i am trying the upload file example .
  The code works fine when i click the send button the file progress bar runs to 100% but i am not sure where it is uploaded ? can we define to upload in certain path..</p>
  
  <pre><code>class HelloApplication: public WApplication {
  public:
      HelloApplication(const WEnvironment&amp; env);
  
  private:
  
      WPushButton *uploadButton;
      Wt::WFileUpload *fu;
  
      void greet();
  };
  
  HelloApplication::HelloApplication(const WEnvironment&amp; env) :
          WApplication(env) {
      root()-&gt;addStyleClass("container");
      setTitle("Hello world");       // application title
  
      fu = new Wt::WFileUpload(root());
      fu-&gt;setFileTextSize(50); // Set the maximum file size to 50 kB.
      fu-&gt;setProgressBar(new Wt::WProgressBar());
      fu-&gt;setMargin(10, Wt::Right);
  
      // Provide a button to start uploading.
      uploadButton = new Wt::WPushButton("Send", root());
      uploadButton-&gt;setMargin(10, Wt::Left | Wt::Right);
  
      // Upload when the button is clicked.
  
      uploadButton-&gt;clicked().connect(this, &amp;HelloApplication::greet);
  }
  
  void HelloApplication::greet() {
      fu-&gt;upload();
      uploadButton-&gt;disable();
  
  }
  
  WApplication *createApplication(const WEnvironment&amp; env) {
  
      return new HelloApplication(env);
  }
  
  int main(int argc, char **argv) {
      return WRun(argc, argv, &amp;createApplication);
  }
  </code></pre>