Document --use-npm flag

[farhanaslam5151]

create react app command updated as it need to be with --use-npm to clear the confusion

[facebook-github-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file. In order for us to review and merge your code, please sign up at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need the corporate CLA signed.

If you have received this in error or have any questions, please contact us at [email protected]. Thanks!

[farhanaslam5151]

create react app command make confusion to developers as it need to be with --use-npm

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Facebook open source project. Thanks!

[iansu]

I don't think we want to add this to the install command in the README because then everyone will use npm. We specifically use yarn when it's available. If we wanted to use npm all the time then we would just change that code.

The purpose of this flag is to allow people to override the default option of using yarn for troubleshooting any yarn specific issues.

[bugzpodder]

Thanks for the PR. Agree with Ian, CRA uses yarn as the package manager if its already installed so the current example in the README is correct.