`getDomain` uses HTTP_HOST instead of SERVER_NAME.

The `SERVER_NAME` variable does not contain the subdomain all the time,
and more importantly, it does not really contain the domain at all. For
instance:

    # $_SERVER['SERVER_NAME'] === "sub.foo.app"
    server_name     sub.foo.app other.foo.app;

    # $_SERVER['SERVER_NAME'] === "foo.app"
    server_name     foo.app bar.foo.app;

    # $_SERVER['SERVER_NAME'] === "*.foo.app"
    server_name     *.foo.app foo.app;

So we fallback to `HTTP_HOST` as before.

1 files changed, 1 insertions, 1 deletions

diff --git a/Http/Http.php b/Http/Http.php
index 903289f..ce95d8f 100644
--- a/Http/Http.php
+++ b/Http/Http.php
@@ -780,7 +780,7 @@ class Http extends Router\Generic implements Core\Parameter\Parameterizable
                 return $domain = '';
             }
 
-            $domain = $_SERVER['SERVER_NAME'];
+            $domain = $_SERVER['HTTP_HOST'];
 
             if (empty($domain)) {
                 $domain = $_SERVER['SERVER_ADDR'];