Chore: Migrate `LiveView Chat` App from `Heroku` to `Fly.io`

[Nelson]

Sadly, all "free" Heroku Apps will be deleted this month ... ref: dwyl/learn-heroku#52 🤦‍♂️

Todo

• Migrate app to liveview-chat.fly.dev
• Update deployment docs in README.md
• DELETE any files related to Heroku deployment
• Add GIF of working App
• Update URL in repo settings
• DELETE Heroku App! ✂️

[LuchoTurtle]

I've been trying to have a go at this for quite some time.

At first, I was having trouble connecting to the Postgres SQL database due to not having the :ssl configuration present.

** (RuntimeError) SSL connection can not be established because `:ssl` application is not started,
         you can add it to `extra_applications` in your `mix.exs`:

But now I keep getting an error at the end of the deployment phase...

 1 desired, 1 placed, 0 healthy, 1 unhealthy
--> v1 failed - Failed due to unhealthy allocations - no stable job version to auto revert to and deploying as v2 

Will investigate further, I guess

[Nelson]

@LuchoTurtle this will need to be updated to the latest Phoenix before it can be deployed to Fly.io ...
Please consider working on this one instead: dwyl/app#312

[LuchoTurtle]

Pushed #111 nonetheless so anyone can pick up where it was left off 👍