nginx redirect to https

if ($scheme != "https") {
	return 301 https://$host$request_uri;
}

set $do_redirect 1;
if ($scheme ~* ^https$) {
	set $do_redirect 0;
}
if ($request_uri ~* ^/robots\.txt$) {
	set $do_redirect 0;
}
if ($do_redirect = 1) {
	return 301 https://$server_name$request_uri;
}