Redirect /about/how_to_help to /volunteer

Relates to #20

_env/nginx.conf

@@ -93,6 +93,7 @@ http {
     }
 
     rewrite /schools/how_to_enter https://studentrobotics.org/compete redirect;
+    rewrite /about/how_to_help https://studentrobotics.org/volunteer redirect;
     rewrite /sponsors https://studentrobotics.org/contact redirect;
     rewrite /key_dates https://studentrobotics.org/events redirect;