Update Subscriptions Ellie example using external Phoenix transport code

[dillonkearns]

Now that the transport layer code has moved out of dillonkearns/elm-graphql based on #43, we should have an Ellie example linked to in the README to illustrate how this could be done (as this comment points out).

This may have to wait until the elm/websocket package, and perhaps a package for Elm and Phoenix, are published. This package uses long polling with Phoenix as a workaround, but is listed as not being production ready yet so it might be best to hold off for now.

[knewter]

I'm setting it up right now with @absinthe/socket and ports, might be worth showing that off.

[dillonkearns]

@knewter yes please! I'd love to get a working example from you, and then I can update the Ellie example to use the same as pattern 👌👌

[knewter]

I'll release the underlying app open source in the next couple of weeks, but for now here's the general pattern: https://gist.github.com/knewter/6c95a14d03ad038db32f5e5c5852d800

[dillonkearns]

I am super grateful to you for sharing this, @knewter, thank you! I just got my subscriptions demo from 0.18 working locally. Now I just need to package it up so that I can post it as a live demo. I'll post an update here once I do and close this out 👍

[dillonkearns]

I published a live demo based on your example @knewter. Thank you so much for the help! I linked to the demo and its source code in the README so I think we can call this done. Please don't hesitate to follow up here or in slack if you have any suggestions for how to make the example or docs better. Thanks!