Create trello cards from errors using webhook

• implement trello card via rest api
• process webhook response body from error monitoring tools
• add trello label for cards resolved/unresolved
• add Github project (kanban, automation)
• add Cachex for retrieving list id and labels
• verify webhook signature (security)
• add code docs (typespecs, docs/moduledocs)
• use markdown for creating card description (TBA)
• add Credo (code linter)
• add Sobelow (security checker for framework)
• add Honeybadger (error monitoring)
• add Uptimerobot (uptime monitoring)
• add Logflare (log aggregator)
• add ci workflow (unit, mocks)
• add code coverage (deps, ci)
• add badge (ci, coverage, dependabot, etc.)
• add semver
• update README file to contain instructions from Trello, error monitoring tool and sample deployment for Phoenix framework
• publish docs (hexdocs for Phoenix framework)
• add cd workflow (fly.io)

To start your Phoenix server:

• Install dependencies with mix deps.get
• Don't forget env variables (e.g. export TRELLO_API_KEY=aaaa...)
• Start Phoenix endpoint with mix phx.server or inside IEx with iex -S mix phx.server

You can test the flow locally by:

1. Create a mix project: add error monitoring tool and install e.g. :rollbax to trigger the error. Note: create a route and add the error as a trigger point, or use this sample repo
2. Run ex_trello_notifier on another port (PORT=4444 iex -S mix.phx server).
3. Expose those two apps via tunneling. For this demo, use ngrok.io
4. Add auth token in ngrok.yml, then ngrok start --config=ngrok.yml test notifier.
5. curl https://<DYNAMIC_SUBDOMAIN>.ap.ngrok.io/PATH_IF_ANY.
6. Then check Trello board for changes.

Now you can visit localhost:4000 from your browser.