stunnel doesn't act as a transparent proxy

Problem

• Within rails, request.base_url returns a http:// URL instead of http

• This breaks U2F app_id generation. A U2F app ID needs to be:

  • The same URL that the user has visited
  • A HTTP URL

• Since request.base_url (http) doesn't match the page the user is on (https), U2F doesn't work

Potential Solutions

• Use the tunnelss gem, which acts as a transparent proxy: https://github.com/rchampourlier/tunnelss

/cc @connorshea