[Treantjs]: group coloring nodes

[egor-progger]

Description from treantjs issue

I am playing with visualization using visNetwork. I want group of nodes to have the same color. library(visNetwork) nodes<-data.frame(id=1:9) edges<-data.frame(from =c(1,2,3,4,4,3,5,5), to=c(2,3,4,6,8,5,7,9)) I want {5,7,9} to be of same color and {4,6,8} also be of different color. Your help would be appreciated. Thank you

Treantjs issue link

fperucic/treant-js#149