feature for data storing

[toposopher]

it'd be great if we can store our state somewhere on the internet!
I suggest the user's personal gist account!

hourly (or user-configured time interval) the time flow would update the gist version, given that user has given PAT(Github personal access token) to TimeFlow settings,

I would work on this if I get time and would send a PR, or if @chiunhau can work on that?