Dumping your homebrew installed packages use the following command
brew bundle dump
This creates a Brewfile under the current directory. You can also write this from scratch easily and the specs are fairly easy. To install all packages from Brewfile run the following command
brew bundle
If you don't want download manually from Mac App Store, you can use Mas utility which download all specified apps from App Store for you automatically.
mas install wunderlist
Note: For apps installed from Mas you need to specify explicitly the id of app. If you don't know id, just run
mas search wunderlist // 410628904
Use this id with the name of app in your Brewfile config
mas "Wunderlist", id: 410628904