Creation Initial channel

Updated the user model with a create_initial_channel method in order to avoid application failure upon admin creation ( "cannot find channel[id] = 1")
In the ```Deploy.md``` file, it tells you to run ```rake db:migrate``` and  ```rake kandan:bootstrap``` (using ```kandan.rake```), which creates an initial user and channel. I don't believe it shouldn't be the job of the User model to create a channel if one doesn't exist.

To be fair, I think under this same premise ensuring there's at least one admin (```:ensure_at_least_one_admin```) in an after_create isn't warranted as well -- this is a one-off task that is done when the app is deployed, something not needed to be checked every time a new user is created.