On the overview in gnome-shell, there are two search buttons for Google and Wikipedia. Is it possible to create a similar button for Ask Ubuntu?
I have found fossfreedom's answer to create a DuckDuckGo search button in gnome-shell to be useful and I have used it as a base to answer this question.
To create a new search provider, copy the google.xml file as a template.
Change the following XML tags in the askubuntu.xml file:
If you have done everything right, you should be seeing the Ask Ubuntu search button in the overview.