Documentation to help windows contributors (facebook#2841)

* Added documentation for contributors using windows 10

Hopefully encourages devs on Windows machine to contribute

* corrected the wordings a little

Author: Dubes

CONTRIBUTING.md

@@ -96,6 +96,21 @@ and then run `npm start` or `npm run build`.
 
 More detailed information are in the dedicated [README](/packages/react-scripts/fixtures/kitchensink/README.md).
 
+## Tips for contributors using Windows
+
+The scripts in tasks folder and other scripts in `package.json` will not work in Windows out of the box. However, using [Bash on  windows](https://msdn.microsoft.com/en-us/commandline/wsl/about) makes it easier to use those scripts without any workarounds. The steps to do so are detailed below: 
+
+### Install Bash on Ubuntu on Windows
+
+A good step by step guide can be found [here](https://www.howtogeek.com/249966/how-to-install-and-use-the-linux-bash-shell-on-windows-10/)
+
+### Install Node.js and npm
+Even if you have node and npm installed on your windows, it would not be accessible from the bash shell. You would have to install it again. Installing via [`nvm`](https://github.com/creationix/nvm#install-script) is recommended.
+
+### Line endings
+
+By default git would use `CRLF` line endings which would cause the scripts to fail. You can change it for this repo only by setting `autocrlf` to false by running `git config core.autocrlf false`. You can also enable it for all your repos by using the `--global` flag if you wish to do so.
+
 ## Cutting a Release
 
 1. Tag all merged pull requests that go into the release with the relevant milestone. Each merged PR should also be labeled with one of the [labels](https://github.com/facebookincubator/create-react-app/labels) named `tag: ...` to indicate what kind of change it is.