Added a ".gitkeep" to the wp dir

This way the wp directory will exist in the repo :-)
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Merge branch 'master' of github.com:schmkr/wp-skeleton-cli

* 'master' of github.com:schmkr/wp-skeleton-cli:
  Removed the "todo" syntax, just a bullet list now.
  Update README.md
  Updated todo list in README.md