code: protected static void setAppURL(Selenified clazz, ITestContext context, String siteURL) {
          context.setAttribute(clazz.getClass().getName() + APP_URL, siteURL);
      }
docs: Sets the URL of the application under test. If the site was provided as a
  system property, this method ignores the passed in value, and uses the
  system property.
  
  @param clazz   - the test suite class, used for making threadsafe storage of
  application, allowing suites to have independent applications
  under test, run at the same time
  @param context - the TestNG context associated with the test suite, used for
  storing app url information
  @param siteURL - the URL of the application under test