[Added] Tests and some more functionality to the Services

backend/src/main/java/com/ninjaws/quiz/models/Session.java

@@ -0,0 +1,18 @@
+package com.ninjaws.quiz.models;
+
+import java.util.List;
+import java.util.UUID;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class Session {
+    private final String id;
+    private List<Question> questions;
+
+    public Session() {
+        this.id = UUID.randomUUID().toString();
+    }
+}