More bindings.

app/Models/Category.php

@@ -1,11 +1,13 @@
 <?php namespace FireflyIII\Models;
 
+use Auth;
 use Carbon\Carbon;
 use Crypt;
 use FireflyIII\User;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 
 /**
  * FireflyIII\Models\Category
@@ -111,4 +113,14 @@ class Category extends Model
         return $this->belongsTo('FireflyIII\User');
     }
 
+    public static function routeBinder(Category $value)
+    {
+        if (Auth::check()) {
+            if ($value->user_id == Auth::user()->id) {
+                return $value;
+            }
+        }
+        throw new NotFoundHttpException;
+    }
+
 }