Add Replicate demo and API

[chenxwh]

Hi @csslc ,

Great work on DDColor!

This pull request makes it possible to run DDColor on Replicate (https://replicate.com/cjwbw/DDColor) and via API (https://replicate.com/cjwbw/DDColor/api). Also happy to transfer the demo page to you so you can make modifications easily :)

[piddnad]

Hi @chenxwh ,
Thank you for your contribution!
It would be helpful if you could add some information to the News and Online Demo sections. I noticed that you included it in the initial commit, but it appears to have been overwritten by a subsequent commit.
My replicate account is piddnad. I would greatly appreciate it if you could add me to the project.

[chenxwh]

Hi @piddnad,

Sure! I have updated the README to include the News section. Also, the demo page is redirected to your account here https://replicate.com/piddnad/ddcolor!

[piddnad]

Hi, @chenxwh ,
Thank you! :)
I will merge the pull request into the master branch.