The custom dictionary is found at https://github.com/pressgang-ccms/PressGangCCMSUI/blob/Development/src/main/webapp/javascript/typojs/en_US-custom.dic If any additional words are required, fork the project and edit that file.
Spell checking and spelling suggestions are now implemented.
Only feedback is that if there are no spelling suggestions, it takes quite a while to respond. If there are suggestions, it seems much quicker. I'm in Firefox.