Print stack traces for internal errors

src/main/java/net/frozenorb/apiv3/util/ErrorUtils.java

@@ -21,6 +21,7 @@ public class ErrorUtils {
     }
 
     public static void respondInternalError(RoutingContext ctx, Throwable error) {
+        error.printStackTrace();
         respondGeneric(ctx, 500, "Internal error: " + error.getClass().getSimpleName());
     }