Pinning Apps to dock VIA terminal or installation arguments OS Sierra
You can use the following command (replace PATH_TO_YOUR_APP):

defaults write com.apple.dock persistent-apps -array-add "&lt;dict&gt;&lt;key&gt;tile-data&lt;/key&gt;&lt;dict&gt;&lt;key&gt;file-data&lt;/key&gt;&lt;dict&gt;&lt;key&gt;_CFURLString&lt;/key&gt;&lt;string&gt;PATH_TO_YOUR_APP&lt;/string&gt;&lt;key&gt;_CFURLStringType&lt;/key&gt;&lt;integer&gt;0&lt;/integer&gt;&lt;/dict&gt;&lt;/dict&gt;&lt;/dict&gt;"

This adds the application to the dock. For the change to take effect, follow this up with killall cfprefsd and killall Dock.