docs: add "Overwriting Existing File"

Author: kenjis

user_guide_src/source/libraries/uploaded_files.rst

@@ -324,6 +324,18 @@ You can specify a new filename by passing it as the second parameter:
 
 .. literalinclude:: uploaded_files/017.php
 
+By default, if the destination file already exists, a new filename will be used.
+For example, if **image_name.jpg** already exists in the directory, then the
+filename will be **image_name_1.jpg**.
+
+Overwriting Existing File
+-------------------------
+
+You can overwrite the existing file by passing ``true``
+as the third parameter:
+
+.. literalinclude:: uploaded_files/022.php
+
 Check if the File Moved
 -----------------------
 

user_guide_src/source/libraries/uploaded_files/022.php

@@ -0,0 +1,3 @@
+<?php
+
+$file->move(WRITEPATH . 'uploads', null, true);