Fix setting the Host header (bensie#1)

* Update to hit localhost

This change will allow us to add 127.0.0.1 to the list or allowed hosts in
Rails 6

* Turns out, go overwrites the Host header

It looks at the requests Host property, and if it's not set it falls back to the
URL's host

* We don't need to change the ip when setting the host property

Add readme