Update ReadMe.txt

Added a note about leaving data folders intact when updating portable version of CodeSnip.

Author: delphidabbler

Docs/ReadMe.txt

@@ -132,6 +132,10 @@ code snippets.
 No files are written outside the folder where you copied the files and the
 registry is not modified.
 
+** WARNING: When updating an existing portable installation with a new version
+of CodeSnip it is important that you do not change or delete the AppData and
+UserData folders. If you do this you risk loosing your settings and/or database.
+
 
 Uninstallation
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