add git alias 'gcmsg' and stand for 'git commit -m'

plugins/git/git.plugin.zsh

@@ -23,9 +23,10 @@ compdef _git gc=git-commit
 alias gca!='git commit -v -a --amend'
 compdef _git gca!=git-commit
 alias gcmsg='git commit -m'
-compdef _git gcm=git-commit
+compdef _git gcmsg=git-commit
 alias gco='git checkout'
 compdef _git gco=git-checkout
+alias gcm='git checkout master'
 alias gr='git remote'
 compdef _git gr=git-remote
 alias grv='git remote -v'