doc: preliminary changelog update

_dist/README.txt

@@ -18,6 +18,7 @@ You can use contented as a standalone upload server, or you can use the SDK to e
 - Detect duplicate upload content and reuse storage
 - Options to limit the upload filesize and the upload bandwidth
 - Short URLs (using [url=http://hashids.org]Hashids[/url] algorithm)
+- Image thumbnailing
 
 =USAGE (SERVER)=
 
@@ -48,6 +49,7 @@ The server responds on the following URLs:
 
 - `/get/{ID}`: Download item content
 - `/info/{ID}`: Get item content metadata (JSON)
+- `/thumb/{Type}/{ID}`: Get item thumbnail image
 - `/about`: Get server metadata (JSON)
 
 =USAGE (EMBEDDING FOR WEB)=
@@ -60,6 +62,9 @@ contented.init("#target", function(/* String[] */ items) {});
 
 =CHANGELOG=
 
+?: 1.2.0
+- Feature: Thumbnail support
+
 2017-10-15: 1.1.0
 - Feature: Drawing mode
 - Feature: Ctrl+V image upload