There is an officially supported extension, "Auto move windows", that will move applications to a specific workspace. Install the package "gnome-shell-extensions" to have this and other officially supported gnome shell extensions available for all users on the system. Alternatively, you may install extensions from the Gnome Shell extensions website, but that way is not as such officially supported by Canonical, the maker of Ubuntu.
A more traditional way, that will work on a multitude of desktops running on the Xorg display server, is to use devilspy. With devilspy, you can, among others, define that windows belonging to a specific application, or having a specific window title, should be moved to a specific workspace when they are created.