Add Campaigns module for grouping QR codes.

Let accounts organise codes by promo or launch, attach or detach codes, and view combined scan totals from the sidebar.

app/Models/User.php

@@ -58,6 +58,11 @@ class User extends Authenticatable
         return $this->hasMany(QrCode::class);
     }
 
+    public function campaigns(): HasMany
+    {
+        return $this->hasMany(Campaign::class);
+    }
+
     public function qrSetting(): HasOne
     {
         return $this->hasOne(QrSetting::class);