Update documentation

CHANGELOG.md

@@ -1,7 +1,16 @@
 3.10.0
 ========================
 * New post-processing
+* Added support for thumbnails with different aspect ratios than 4:3
 * Fix: MV Live models with spaces in the name not indicated as recording
+* Fix: MV Live recordings stop every few minutes, if recorded with server
+* Fix: Kind of fixed Showup.tv recordings. It does record now, but the
+  recordings now stop after a couple of minutes, because the now require you
+  to be logged in. This has to be addressed in a future release
+* Removed setting to delete too short recordings. This is now a post-process
+  step, which has to be added in the settings
+* Removed setting to remove a recording after post-processing. This is now
+  a post-process step, which has to be added in the settings
 
 3.9.0
 ========================

client/src/main/resources/html/docs/PostProcessing.md

@@ -25,6 +25,19 @@ the files to another format, create preview images, rename / move the file etc.
 - **create timeline thumbnails** - create a small thumbnail for every second or every few seconds, which can be used to very fast
   scan through a recording
 
+#### How to configure the server to do post-processing
+There is currently no user interface to configure the post-processing for the server. It has to be added manually to the server config.
+I suggest to start the app and configure the post-processing steps in the settings. Afterwards you close the app and copy the
+post-processing section from the settings.json to your server.json file. To find out, where these files are on your system, read
+[Configuration File](ConfigurationFile.md).
+
+The part you have to copy is
+```
+  postProcessors: [
+    ...
+  ],
+```
+
 #### Variables
 
 <a id="variables" />