Add Stack middleware that allow redirecting to another stack

lib/middleware/stack.ex

@@ -0,0 +1,14 @@
+defmodule Cage.Middleware.Stack do
+  use Cage.Middleware
+
+  def call(conn, state, opts) do
+    if is_atom(opts), do: opts = [stack: opts]
+    stack = opts[:stack]
+    {conn, state} = stack.run(conn, state)
+    if opts[:stop] == true do
+      stop(conn, state)
+    else
+      {conn, state}
+    end
+  end
+end