They provided the direct link to the apk file. Scroll down in the README.md displayed on the github link to the heading "Android GUI app" found here. The first line of the paragraph has the phrase "Android app" as a link to the drammer.apk file. You can use this to sideload onto your device and perform the check. They also tried to provide a link to the Google Play page for the app in that section of the doc, however it looks like Google disabled it as against the TOS (link now goes to a 404 page).
All that said, this is probably one of those apps you'll want to first read the source and see for yourself what it's doing, then install the Android NDK on a PC to compile it; from there sideload the apk you built. This way you can at least be a little more certain of the build to make sure that it only does exactly what the code says it should...instead of trusting someone else's build to not have any added features