When GnomeSoy installs, it should be registered as the default application for handling SGK files in Gnome. Research what this entails and implement it such that GnomeSoy is opened when a .sgk file is clicked on.

While working on this task you should join and remain in #PySoy on Freenode to get help, feedback, and guidance from mentors and other developers. Code updates which may affect your work are also announced here as they happen.

When you've done, commit your work and post the resulting changeset url to this task.