Replace methods with more flexible endpoints

tests/ui/endpoint/async_state.rs

@@ -0,0 +1,12 @@
+#[macro_use]
+extern crate gotham_restful;
+use gotham_restful::State;
+
+#[derive(Resource)]
+#[resource(read_all)]
+struct FooResource;
+
+#[read_all]
+async fn read_all(state: &State) {}
+
+fn main() {}