Add dev mode

src/main.rs

@@ -15,6 +15,10 @@ struct Config {
     #[clap(long, default_value = "127.0.0.1:8000", value_parser)]
     /// The address on which to listen
     address: SocketAddr,
+    #[clap(long, action)]
+    /// Whether to start the server in dev mode; this enables some
+    /// nice handlebars features that are not intended for production
+    dev_mode: bool,
 }
 
 struct SharedData<'a> {
@@ -88,6 +92,7 @@ async fn main() -> Result<(), std::io::Error> {
     handlebars
         .register_templates_directory(".html", config.template_directory.clone())
         .expect("templates should compile correctly");
+    handlebars.set_dev_mode(config.dev_mode);
 
     let shared_data = web::Data::new(SharedData {
         handlebars,