feat: Implement all Frontend stubs

backend/src/api/user.ts

@@ -31,6 +31,14 @@ userRouter.get("/logout", async (req, res) => {
     });
 });
 
+// TODO: This should be shared with the frontend, to remove code duplication
+export enum VocabType {
+    NOMEN = 0,
+    VERB = 1,
+    ADJEKTIV = 2,
+    ADVERB = 3,
+};
+
 // Gets the user's review queue
 userRouter.get("/queue", async (req, res) => {
     console.log("STUB: /user/queue");
@@ -38,7 +46,19 @@ userRouter.get("/queue", async (req, res) => {
     // TODO: Stub
     res.send({
         error: "0",
-        data: {},
+        data: {
+            queue: [{
+                german: ["Wein"],
+                hint: "Worte auf '-um' sind meistens NeutrUM",
+                type: VocabType.NOMEN,
+                latin: {
+                    grundform: "Vinum",
+                    genitiv: "Vini",
+                    genus: "Neutrum"
+                },
+                id: 0
+            }]
+        },
     });
 });