Add not-found error handler

frontend/renderer/error.go

@@ -0,0 +1,14 @@
+package renderer
+
+import (
+	"code.tokarch.uk/mainnika/nikita-tokarch-uk/frontend/content"
+	routing "github.com/jackwhelpton/fasthttp-routing/v2"
+)
+
+// errorNotFound renders http error-404 template
+func (r *Renderer) errorNotFound(c *routing.Context) (err error) {
+
+	errorContent := content.Error{Message: "not found"}
+
+	return c.Write(errorContent)
+}

frontend/renderer/renderer.go

@@ -29,6 +29,7 @@ func (r *Renderer) init() {
 	router := routing.New()
 
 	router.Use(r.useTemplateWriter)
+	router.NotFound(r.errorNotFound)
 
 	r.router = router
 	r.handler = router.HandleRequest