Add #<< alias for #write to ActionDispatch::Response::Buffer

This makes the stream object a closer analog of an `IO`.

on-behalf-of: @Cofense <[email protected]>

Author: elebow

actionpack/lib/action_dispatch/http/response.rb

@@ -126,6 +126,7 @@ def write(string)
         @response.commit!
         @buf.push string
       end
+      alias_method :<<, :write
 
       def each(&block)
         if @str_body