Create a price data chart

[heyajulia]

It'd be nice if the bot also sent a chart to make the data available in a different way that might be easier to scan, depending on context. I've been experimenting a bit with Seaborn, and I like what I've been able to do with it relatively quickly, although it's nowhere near as pretty as I'd like it to be, and it would be quite a challenge to use it from Go.

[!WARNING]

This chart does not contain the actual data; I generated it using random.uniform.

[heyajulia]

There are just a few more things left to do:

• [ ] I think it would look cool if the top of each bar were rounded
• [ ] And, eventually (sigh), I should port the code to something that's a little bit easier to deploy alongside the binary
• [x] The chart might be confusing or impossible to understand for people who are colorblind. I should fix that.
• [x] I should use the regular (non-tnum) font for the title
• [x] It would be nice if we could use Inter's tnum feature to make sure the hours are aligned
• [x] I'd like to change the font to Inter

[heyajulia]

This is the final result for now. I've addressed the most urgent TODOs and am incredibly pleased with how well it turned out.