Create .gitignore even if a git repository has already been initialized

[abillingsley]

A .gitignore is added in the resulting folder structure if it is determined that git has not been initialized yet. In mono-repo scenarios, we likely still want to have a .gitignore

# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.

# dependencies
/node_modules
/.pnp
.pnp.js

# production
/dist

# misc
npm-debug.log*
yarn-debug.log*
yarn-error.log*