The recently released Freedrum has no official Linux support. But, fortunately, it uses standard Bluetooth LE MIDI. It doesn't seem to work out of the box, yet (on Ubuntu 17.04, most probably Ubuntu 18.04 will support it directly).
One really needs bluez 5.46 or higher. On Ubuntu, these are packaged in artful proposed (amd64). Unfortunately, MIDI support is not enabled in this build (Ubuntu bug #1713017).
So you'll need to download the sources, install dependencies plus libasound2-dev, build and install resulting debs. You may need to add --enable-midi to debian/rules. Like this: