How to remap "jj" or "jk" to Escape in Atom when using vim-mode

gistfile1.coffee

# Built from a couple of comments at https://github.com/atom/vim-mode/issues/334
# In ~/.atom/init.coffee
atom.workspaceView.command 'insert-incomplete-keybinding', (e)->
  if oe = e.originalEvent && e.originalEvent.originalEvent
    char = String.fromCharCode(oe.which)
    char = char.toLowerCase() unless oe.shift
    atom.workspace.activePaneItem.insertText(char)

# In ~/.atom/keymap.cson
'.editor.vim-mode.insert-mode':
  'j': 'insert-incomplete-keybinding'

# I prefer jj
'.vim-mode.insert-mode:not(.mini)':
  'j j': 'vim-mode:activate-command-mode'

# Others prefer jk
#'.vim-mode.insert-mode:not(.mini)':
#  'j k': 'vim-mode:activate-command-mode'