[Added] Most of the frontend, split up backend services

backend/src/main/java/com/ninjaws/quiz/services/QueueService.java

@@ -0,0 +1,27 @@
+package com.ninjaws.quiz.services;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+import org.springframework.stereotype.Service;
+
+import com.ninjaws.quiz.models.Request;
+
+@Service
+public class QueueService {
+    
+    /**
+     * Stores all user requests for data
+     * Executes them in order, one every 5 seconds (the limit of the external API)
+     * Removes them from the Queue when the request was succesful
+     */
+    private final BlockingQueue<Request> requests = new LinkedBlockingQueue<>();
+
+    public void addToQueue(Request request) {
+        requests.add(request);
+    }
+
+    public Request popFromQueue() {
+        return requests.poll();
+    }    
+}