Prepare an example on how to run MFYNAB in Docker

[davidstosik]

First step towards a deploy process based on Kamal: getting MFYNAB to run in a Docker container.

The hardest parts were:

• getting Chrome(ium) to run in the container on Apple Silicon
• forwarding environment to cron

Note this PR is based on sto/refresh-mf-accounts.

[Copilot]

PR Overview

This PR prepares an example to run MFYNAB in Docker, laying the groundwork for a deploy process based on Kamal.

• Gemfile updated to pull MFYNAB from a specific GitHub branch
• Adjustments to Ferrum configuration in the session for Docker compatibility
• Freshness limit for account status reduced and README updated with Docker run instructions

Reviewed Changes

File	Description
docker_example/Gemfile	Added gem dependency with a FIXME note to update to the latest RubyGems release
lib/mfynab/money_forward/session.rb	Updated Ferrum browser instantiation to support running Chromium as root in Docker
lib/mfynab/money_forward/account_status.rb	Adjusted the freshness limit from 1 day to 1 hour
README.md	Extended documentation with instructions on running MFYNAB with cron and Docker

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

lib/mfynab/money_forward/account_status.rb:70

• The freshness limit has been reduced from 24 hours to 1 hour. Confirm that this shorter interval meets the intended caching or update frequency requirements.

FRESHNESS_LIMIT = 60 * 60 # 1 hour

[Copilot]

Using the 'no-sandbox' option can expose security vulnerabilities. Consider conditionally enabling it only when running in Docker by checking an environment variable to better isolate production and container-specific behavior.

Suggested change

	# FIXME: this was needed to be able to run Chromium headless
	# within Docker as root, but I'd rather not rely on it.
	browser_options: { "no-sandbox": nil },
	browser_options: ENV.key?("IN_DOCKER") ? { "no-sandbox": nil } : {},
	# FIXME: this was needed to be able to run Chromium headless
	# within Docker as root, but I'd rather not rely on it.