Integrate Prettier about relay-starter-kit

[pruhstal]

Wouldn't it make more sense to enforce code styling with some eslint rules and not accept anything that doesn't pass a pre-commit hook into this repo?

Seems like there are more things that would be useful to add to this particular project.

[cmmartin]

I personally prefer prettier to eslint, although they can both be used as mentioned in this tweet. This project is already using eslint. The prettier docs include an example of using it alongsideeslint.

[followbl]

@koistya close this one?

[koistya]

@followbl yep, thanks for heads up!