rails-routes: add page (#3922)

pages/common/rails-routes.md

@@ -0,0 +1,20 @@
+# rails routes
+
+> List routes in a Rails application.
+> More information: <https://guides.rubyonrails.org/routing.html>.
+
+- List all routes:
+
+`rails routes`
+
+- List all routes in an expanded format:
+
+`rails routes --expanded`
+
+- List routes partially matching URL helper method name, HTTP verb, or URL path:
+
+`rails routes -g {{posts_path|GET|/posts}}`
+
+- List routes that map to a specified controller:
+
+`rails routes -c {{posts|Posts|Blogs::PostsController}}`