Update docs

Author: Art4

docs/utils-factory.md

@@ -19,8 +19,17 @@ Assuming you want a `toJson()` functionality in your document object. First crea
 
 ```php
 namespace My\Own
-class Document extends \Art4\JsonApiClient\Document
+class Document implements \Art4\JsonApiClient\DocumentInterface
 {
+    // Implement the \Art4\JsonApiClient\DocumentInterface here
+    /*
+    public function get($key);
+    public function has($key);
+    public function getKeys();
+    public function asArray();
+    */
+
+    // your new method
     public function toJson()
     {
         return json_encode($this->asArray(true));

src/Utils/AccessTrait.php

@@ -8,7 +8,7 @@
 trait AccessTrait
 {
 	/**
-	 * Check if a value exists in this document
+	 * Check if a value exists in this object
 	 *
 	 * @param string $key The key of the value
 	 * @return bool true if data exists, false if not
@@ -19,7 +19,7 @@ public function has($key)
 	}
 
 	/**
-	 * Returns the keys of all setted values in this document
+	 * Returns the keys of all setted values in this object
 	 *
 	 * @return array Keys of all setted values
 	 */