added git log with graph

plugins/git/git.plugin.zsh

@@ -27,6 +27,8 @@ alias gcp='git cherry-pick'
 compdef _git gcp=git-cherry-pick
 alias glg='git log --stat --max-count=5'
 compdef _git glg=git-log
+alias glgg='git log --graph --max-count=5'
+compdef _git glgg=git-log
 
 # Git and svn mix
 alias git-svn-dcommit-push='git svn dcommit && git push github master:svntrunk'