We value Open Source and make a point to release all our plugins on GitHub under a BSD License.
Inside Atom, navigate to Preferences (or Settings) → Install and search for wakatime.
Click the Install button.
Click the Settings button inside the wakatime package.
Enter your API key
Use Atom like you normally do and your coding activity will be displayed on your WakaTime Dashboard.
Alternatively, you can install WakaTime from command line with apm install wakatime.
apm install wakatime