Added protection to Nickname and added user get coins endpoint

api/app/Http/Controllers/AuthController.php

@@ -46,6 +46,10 @@ class AuthController extends Controller
         if (User::where('email', $request->email)->exists()) {
             return response()->json(['message' => 'Email already registered'], 409);
         }
+        
+        if (User::where('nickname', $request->nickname)->exists()) {
+            return response()->json(['message' => 'Nickname already registered'], 409);
+        }
 
         $user = User::create([
             'email' => $request->email,