Adds an Entity Presenter to ExpenseCategory

Without the presentable trait and at the basic level a default
EntityPresenter, adding Expense Categories breaks when trying to view
the edit page for the expense.

app/Models/ExpenseCategory.php

@@ -1,6 +1,7 @@
 <?php namespace App\Models;
 
 use Illuminate\Database\Eloquent\SoftDeletes;
+use Laracasts\Presenter\PresentableTrait;
 
 /**
  * Class ExpenseCategory
@@ -9,6 +10,7 @@ class ExpenseCategory extends EntityModel
 {
     // Expense Categories
     use SoftDeletes;
+    use PresentableTrait;
 
     /**
      * @var array
@@ -17,6 +19,11 @@ class ExpenseCategory extends EntityModel
         'name',
     ];
 
+    /**
+     * @var string
+     */
+    protected $presenter = 'App\Ninja\Presenters\EntityPresenter';
+
     /**
      * @return mixed
      */