Add resource for articles

src/Resources/Article/Articles.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace KFoobar\Fortnox\Resources\Article;
+
+use KFoobar\Fortnox\Interfaces\ClientInterface;
+use KFoobar\Fortnox\Interfaces\ResourceInterface;
+use KFoobar\Fortnox\Traits\HasCreate;
+use KFoobar\Fortnox\Traits\HasDelete;
+use KFoobar\Fortnox\Traits\HasRetrieve;
+use KFoobar\Fortnox\Traits\HasUpdate;
+
+class Articles implements ResourceInterface
+{
+    use HasCreate;
+    use HasDelete;
+    use HasRetrieve;
+    use HasUpdate;
+
+    protected $endpoint = 'articles';
+
+    /**
+     * Constructs a new instance.
+     *
+     * @param \KFoobar\Fortnox\Interfaces\ClientInterface $client
+     */
+    public function __construct(ClientInterface $client)
+    {
+        $this->client = $client;
+    }
+}

src/Services/Fortnox.php

@@ -3,6 +3,7 @@
 namespace KFoobar\Fortnox\Services;
 
 use KFoobar\Fortnox\Resources\Account\Accounts;
+use KFoobar\Fortnox\Resources\Article\Articles;
 use KFoobar\Fortnox\Resources\CostCenter\CostCenters;
 use KFoobar\Fortnox\Resources\Currency\Currencies;
 use KFoobar\Fortnox\Resources\Customer\Customers;
@@ -42,6 +43,16 @@ public function accounts()
         return new Accounts($this->client);
     }
 
+    /**
+     * Returns the articles resource.
+     *
+     * @return \KFoobar\Fortnox\Resources\Article\Articles
+     */
+    public function articles()
+    {
+        return new Articles($this->client);
+    }
+
     /**
      * Returns the cost centers resource.
      *