yarn doesn't add global packages bin/ to $PATH

What is the current behavior? yarn doesn't add the directory for commands of globally installed packages (~/.yarn/bin) to $PATH, hence these commands cannot be invoked after having them added using yarn.

What is the expected behavior? PATH is updated to include ~/.yarn/bin by yarn during initial installation or during global package installation so commands can be invoked without requiring extra changes to config/.bashrc.

Please mention your node.js, yarn and operating system version. node v9.2.0 yarn 1.3.2 WSL (Bash on Windows)