Fixed missing port error

src/main/java/tech/nevets/beerestapi/Main.java

@@ -13,7 +13,7 @@ public class Main {
     );
 
     public static void main(String[] args) {
-        if (args[0] != null) {
+        if (args.length >= 1) {
             port(Integer.parseInt(args[0]));
         } else {
             port(8080);