What is "Tom Sawyer's gang"?

The gang was a goup of boys who pretended to be pirates and outlaws.Huck quits Tom's gang because he thinks that if they're not doing anything (robbing people) there's no point to being in a gang. 

"We played robber now and then about a month, and then I resigned.  All the boys did. We hadn't robbed nobody, hadn't killed any people, but only just pretended."