http_proxy setting should respect both parent domain and subdomain
When a ruby app is run in an environment where an http proxy is configured, it is not possible to provide separate settings for both a domain and it's subdomain for outbound http calls. This coupling assumes that both should follow the same http_proxy settings but in practice, this is a common occurrence the parent domain and the subdomains are be hosted on different network.
https://github.com/ruby/ruby/pull/1748 addresses this issues.
Also note that other programming language like go respect different proxy settings for parent domain and its subdomains. https://github.com/golang/go/blob/master/src/net/http/proxy_test.go#L37