[Suggestion] add an option to save revisors

[MarceloMachadoxD]

Hello guys, its a great plugin that helps a lot, an suggestion to add on plugin configuration an option to add revisors

example create an group of revisros for projetct 1, project2 and their e-mails to each one
when we try push we select one or many revisor groups

another suggestion is to save just a list of revisors that always will appear when we try to push to gerrit

the last one is a possibility to select the user groups alreadly created on gerrit (but i think gerrit doesnt recommend do it)