Map remote url in HAProxy

Question

I am currently using apache and mod_proxy to map a local url to a remote url. I am doing this so that https requests will still work properly. In apache I have the following line in my VirtualHost

RewriteRule ^/autocomplete/cities/(.*)$ http://autocomplete.wunderground.com/aq$1 [P]

I am trying to move this to HAProxy now and I am having trouble figuring out how to do this same thing. Here is my current config.

defaults
    mode http
    timeout client  5s
    timeout connect 5s
    timeout server  5s

frontend http x.x.x.x:80
    mode http
    timeout client 120s
    option forwardfor
    default_backend application
    reqadd X-Forwarded-Proto:\ http


frontend https x.x.x.x:81
    mode http
    timeout client 120s
    option forwardfor
    default_backend application
    reqadd X-Forwarded-Proto:\ https


backend application
    balance roundrobin
    server app1 x.x.x.x:80 maxconn 1 check
    server app2 x.x.x.x:80 maxconn 1 check