wit.ai is not called when directly messaging bot

[makstaks]

In botkit-middleware-witai.js, the receive function has this condition:

message.text && message.text.indexOf(bot.identity.id) > -1)

When I directly message the bot, the message.text doesn't contain the bot's identity so this always condition always fails. I want to be able to DM the bot, and have wit.ai process the message.