Added possibility to change Field ID in Contentful (#186)

README.md

@@ -189,6 +189,27 @@ $contentType->unpublish();
 $contentType->delete();
 ```
 
+Changing the ID of a content type field:
+
+``` php
+$oldFieldId = 'oldFieldId';
+$newFieldId = 'newFieldId';
+$contentType = $environmentProxy->getContentType($contentTypeId);
+$field = $contentType->getField($oldFieldId);
+$field->setNewId($newFieldId);
+$fields = $contentType->getFields();
+foreach ($fields as $index => $currentField) {
+    if ($currentField->getId() === $oldFieldId) {
+        $fields[$index] = $field;
+        break;
+    }
+}
+$contentType->setFields($fields);
+$contentType->update();
+$contentType->publish();
+```
+
+
 ### Editor interfaces
 
 Fetching and updating

src/Resource/ContentType/Field/BaseField.php

@@ -27,6 +27,13 @@ abstract class BaseField implements FieldInterface
      */
     protected $id;
 
+    /**
+     * New ID of the Field for renaming.
+     *
+     * @var ?string
+     */
+    protected $newId = null;
+
     /**
      * Name of the Field.
      *
@@ -81,6 +88,21 @@ public function getId(): string
         return $this->id;
     }
 
+    public function getNewId(): ?string
+    {
+        return $this->newId;
+    }
+
+    /**
+     * @return static
+     */
+    public function setNewId(string $newId)
+    {
+        $this->newId = $newId;
+
+        return $this;
+    }
+
     public function getName(): string
     {
         return $this->name;
@@ -220,6 +242,10 @@ public function jsonSerialize(): array
             $data['validations'] = $this->validations;
         }
 
+        if (!is_null($this->newId)) {
+            $data['newId'] = $this->newId;
+        }
+
         return $data;
     }
 }