Add "behind proxy" mode to use forwarded IP headers

helpers/config.go

@@ -12,6 +12,7 @@ type Config struct {
 	App     struct {
 		ListenAddress string `env:"APP_LISTEN_ADDRESS"`
 		ListenPort    uint   `env:"APP_LISTEN_PORT"`
+		BehindProxy   bool   `env:"APP_BEHIND_PROXY"`
 	}
 	Database struct {
 		Location string `env:"DATABASE_LOCATION"`