message: Add links to mailing list and codebase chapter
diff: @@ -206,11 +206,11 @@ We are always happy to get new contributors on board! Please check the
  following table for possible ways to do so:
  | :question: | :bulb: |
  -|:------------------------------------------------------------------------------------------------------|:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
  +|:------------------------------------------------------------------------------------------------------|:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
  | Found a bug? Crashed the app? Broken challenge? Found a vulnerability that is not on the Score Board? | [Create an issue](https://github.com/bkimminich/juice-shop/issues) or [post your ideas in the chat](https://gitter.im/bkimminich/juice-shop) |
  -| Want to help with development? Pull requests are highly welcome! | Please refer to [the _Contribute to development_ chapter](https://bkimminich.gitbooks.io/pwning-owasp-juice-shop/content/part3/contribution.html) of our companion guide ebook |
  +| Want to help with development? Pull requests are highly welcome! | Please refer to the [_Contribute to development_](https://bkimminich.gitbooks.io/pwning-owasp-juice-shop/content/part3/contribution.html) and [_Codebase 101_](https://bkimminich.gitbooks.io/pwning-owasp-juice-shop/content/part3/codebase.html) chapters of our companion guide ebook |
  | Want to help with internationalization? | Find out how to join our [Crowdin project](https://crowdin.com/project/owasp-juice-shop) in [the _Helping with translations_ documentation](https://bkimminich.gitbooks.io/pwning-owasp-juice-shop/content/part3/translation.html) |
  -| Anything else you would like to contribute? | Write an email to bjoern.kimminich@owasp.org |
  +| Anything else you would like to contribute? | Write an email to owasp_juice_shop_project@lists.owasp.org or bjoern.kimminich@owasp.org |
  ## References
  @@ -240,8 +240,10 @@ a new challenge!
  We're also happy to supply you with stickers if you organize a meetup or
  conference talk where you use or talk about or hack the OWASP Juice
  -Shop! Just contact the project leader to discuss your plans:
  -bjoern.kimminich@owasp.org!
  +Shop! Just
  +[contact the mailing list](mailto:owasp_juice_shop_project@lists.owasp.org)
  +or [the project leader](mailto:bjoern.kimminich@owasp.org) to discuss
  +your plans! !
  ## Donations
  