I've released a new application called MaruNote.
This is an online notebook behaves really same way with a physical notebook. You don't need to buy notebooks anymore!
It's implemented Elixir/Phoenix and distributed by ReactNative for mobile apps.(Of course, you can enjoy this on a browser as well.)
Also, I've made it public how to deploy Elixir/Phoenix app. If you're interested in it, check it out, please.