add resource map, it allow to check if router has resource and it allows to generate urls for named resources

src/error.rs

@@ -0,0 +1,20 @@
+pub use actix_http::error::*;
+use derive_more::{Display, From};
+use url::ParseError as UrlParseError;
+
+/// Errors which can occur when attempting to generate resource uri.
+#[derive(Debug, PartialEq, Display, From)]
+pub enum UrlGenerationError {
+    /// Resource not found
+    #[display(fmt = "Resource not found")]
+    ResourceNotFound,
+    /// Not all path pattern covered
+    #[display(fmt = "Not all path pattern covered")]
+    NotEnoughElements,
+    /// URL parse error
+    #[display(fmt = "{}", _0)]
+    ParseError(UrlParseError),
+}
+
+/// `InternalServerError` for `UrlGeneratorError`
+impl ResponseError for UrlGenerationError {}