There are three ways to do so.
A: If you are using Astah Professional, you can save .asta file in XML file. So managing .asta file in XML with Github is one way.
B: Please refer to the document here.
C: We have a plug-in to let Astah work with Subversion. (This plug-in works with Subversion 1.7)
- Check out the directory from the repository
- Download this plug-in file from here
- Launch Astah and go to [Plugin] - [Installed Plugins] (If you are using version 7.1 or earlier, go to [Help] - [Plugin List])
- [plugins] dialog appears, click [Install] button and select the .jar file you downloaded at step.2
- Restart Astah, then you will find [Simple SVN operation] menu under [Tools]
- Go to [Configuration] menu and set it up
We're sorry but currently documentations about this plug-in isn't available.