Annotator Categories is a plugin developed by Michael Widner for Lacuna Stories (http://www.lacunastories.com). It allows users to choose categories for their annotations and to color the highlights in the text according to which category was chosen.
This is an Annotator.js plugin. The main things to know are that the CSS file is required and is where you set the colors for categories. The plugin also expects options to be passed when initialized that include an array of the categories you want to use.