Consider rewriting bin/flashcards as a Docker wrapper

[botanicus]

• Rename the current bin/flashcards to something else.
• Change the Dockerfile to reflect the change.
• Create bin/flashcards that behaves similarly to Rakefile, but is to be used as the runner out of the dev context. So this would be the primary interface.
• Modify flashcards init to pull the Docker image unless already present.
• Update the documentation.

_{Sent with GitHawk}