Please note that the current version of the source code does not run, and is unlikely to be updated further.
Notifier is no longer available on the AppCenter. If you really wish to install Notifier, see the Releases tab, and use the most current version.
sudo apt install valac libgtk-3-dev libgranite-dev libsqlite3-dev meson elementary-sdk
Use meson to build
meson build --prefix=/usr
Change into build directory
cd build
ninja
Install using ninja install, then run with com.github.timecraft.notifier or by clicking on it in your launcher.
sudo ninja install
com.github.timecraft.notifier
If something is acting funny, or if you just want to see my musings, then execution in the terminal will give you all of that.
com.github.timecraft.notifier