Allow setting site_url

src/main/java/tk/draganczuk/url/App.java

@@ -36,6 +36,7 @@ public class App {
 			get("/all", Routes::getAll);
 			post("/new", Routes::addUrl);
 			delete("/:shortUrl", Routes::delete);
+			get("/siteUrl", Routes::siteUrl);
 		});
 
 		get("/:shortUrl", Routes::goToLongUrl);

src/main/java/tk/draganczuk/url/Routes.java

@@ -42,6 +42,10 @@ public class Routes {
 		}
 	}
 
+	public static String siteUrl(Request req, Response res) {
+		return System.getenv().getOrDefault("site_url", "unset");
+	}
+
 
 	public static String goToLongUrl(Request req, Response res) {
 		String shortUrl = req.params("shortUrl");