class Git::Branch

def in_branch (message = 'in branch work')

end
return true # auto commits and switches back
# do other stuff
# create new file
g.branch('new_branch').in_branch do 
def in_branch (message = 'in branch work')
  old_current = @base.lib.branch_current
  checkout
  if yield
    @base.commit_all(message)
  else
    @base.reset_hard
  end
  @base.checkout(old_current)
end