Documentation suggestion

[agahkarakuzu]

First of all, thank you so much for putting together a great documentation, it helps me a lot in adapting buffy for NeuroLibre tasks!

Regarding the complete example for docs/responders/github_action, it would be really useful to replace it with an example from the actual code, e.g.:

    github_action:
      - draft_paper:
          command: generate pdf
          workflow_repo: openjournals/joss-papers
          workflow_name: draft-paper.yml
          workflow_ref: master
          description: Generates the pdf paper
          data_from_issue:
            - branch
            - target-repository
            - issue_id
          mapping:
            repository_url: target-repository

and mentioning that this example is from this config that lives under the joss branch of buffy.

Having a concrete example would ease understanding the origin and destination of the request, as well as its flow throughout the system. Visualizing it mentally can be tricky since it involves a chain of requests. I was quite puzzled till I realized that buffy was deployed to heroku from the joss branch :)

I am happy to send a PR if you think that this is useful.

[xuanxu]

Good suggestion. PR definitely welcome!