Add Replicate demo and API

[chenxwh]

Hey @amirhertz! 👋

This pull request makes it possible to run your model inside a Docker environment, which makes it easier for other people to run it. We're using an open source tool called Cog to make this process easier.

This also means we can make a web page where other people can run your model! View it here: https://replicate.com/cjwbw/prompt-to-prompt

Replicate also have an API, so people can easily run your model from their code:

import replicate
model = replicate.models.get("cjwbw/prompt-to-prompt")
output = model.predict(original_prompt="pink bear riding a bicycle")

You are more than welcome to modify the Replicate page (e.g. Example Gallery), let me know and I can transfer ownership to your Replicate account or under https://replicate.com/google-research.

In case you're wondering who I am, I'm from Replicate, where we're trying to make machine learning reproducible. We got frustrated that we couldn't run all the really interesting ML work being done. So, we're going round implementing models we like. 😊