Code-push tab completion

Adding tab completion to the CodePush CLI (https://github.com/Microsoft/code-push). Bash only as of now.

Quick start

1. Copy complete.sh into a static location
2. From command prompt, run source path/to/complete.sh
3. You now have tab completion for code-push cli

In order to persist completion across sessions, add the source path/to/complete.sh line to your bash profile (usually at ~/.bash_profile. See the documentation for more shell initialization information)