add new words to kaldi models

[saireddy12]

i have downloaded pre-trained librispeech model link
and want to extend the vocab (add more words that can be recognised by the model)
after reading some docs i found that _dictation file is used to add the words ( that are added in the user_lexicon.txt ) to grammar and fst . for adding words to kaldi model using this repo it seems it needs to be first made compatible to update it , but i need to just add words to kaldi models i don't want to use this repo for any other extra task
is there are simpler/ better or any other way to add words to existing kaldi models

Thanks..