cli: Provide an init command

[marionebl]

As seen in #47 setup currently easily allows for errors in documentation and frustration for users. Add an commitlint init [--extends] command. It should

• create a new commitlint.config.js file if needed, prefer package.json if available

• ensure @commitlint/cli

  • install/update @commitlint/cli as needed

• add configs provided via --extends to module.exports.extends

  • default to @commitlint/config-conventional
  • support multiple --extends
  • check if values are available if npm ids
  • install/update @commitlint/config-* as needed
  • disable via --no-config

• ensure husky

  • ensure presence of commitmsg run-script
  • disable via --no-husky

• add @commitlint/travis-cli to .travis.yml if file is found and not in scripts

  • install/update @commitlint/travis-cli as needed
  • disable via --no-travis

• optional: respect .editorconfig? overkill

[marionebl]

Another reason: #52

[jlegrone]

I wrote create-semantic-module to help address this setup problem. After jlegrone/create-semantic-module#9 is closed all of your bullet points will be covered with the exception of respecting .editorconfig. 😄

[marionebl]

@jlegrone create-semantic-module looks really useful! One of the things I'd like to achieve with init is requiring no prompts by default, is that possible when using yeoman under the hood?

[jlegrone]

@marionebl yes! Sorry I meant to reply sooner, I'll be adding a few more issues to the repo to track these as todos. I also plan to add an option to disable creating a .yo-rc.json file since that would probably be an undesirable side-effect when not running in an "interactive" mode.