add proxy-port for port override when running behind a proxy

Signed-off-by: Adam Crowder <adam@adamcrowder.net>

cmd/cmd.go

@@ -91,6 +91,12 @@ var globalFlags = []cli.Flag{
 		Value: "",
 		EnvVar: "PROXY_PATH",
 	},
+	cli.StringFlag{
+		Name:  "proxy-port",
+		Usage: "port of the proxy when the service is run behind a proxy",
+		Value: "",
+		EnvVar: "PROXY_PORT",
+	},
 	cli.StringFlag{
 		Name:  "ga-key",
 		Usage: "key for google analytics (front end)",
@@ -299,6 +305,10 @@ func New() *Cmd {
 			options = append(options, server.ProxyPath(v))
 		}
 
+		if v := c.String("proxy-port"); v != "" {
+			options = append(options, server.ProxyPort(v))
+		}
+
 		if v := c.String("ga-key"); v != "" {
 			options = append(options, server.GoogleAnalytics(v))
 		}