Work with utf8mb4

[gdomingu]

Hi there, I noticed that when using this gem emojis get converted to four of the replacement characters (����). Wondering if it would be possible to include maybe a setting or something to also work with utf8mb4 characters.

[whitequark]

Feel free to send a PR, I haven't used Ruby in years.

[ndbroadbent]

Hi @gdomingu, I've just started using rack-utf8_sanitizer in my project, and I'm looking at all of the open issues to see if there are any problems I should be aware of.

I've just added a new test case in my app to ensure that people can enter emoji characters into inputs and use these as name or title attributes etc. I haven't seen any problems with this so far.

Is this still a problem for you? Where are the utf8mb4 characters getting broken in your app?

(P.S. Sorry to bother you whitequark!)