Fix belongsToMany example

I noticed that the user model is doing a `belongsToMany(User)` and I
figured you probably meant `belongsToMany(Account)`.
Merge pull request #16 from jgable/fixBelongsToManyExample

Fix belongsToMany example
minor doc fix on when version listed
Merge branch 'master' of github.com:tgriesser/bookshelf

* 'master' of github.com:tgriesser/bookshelf:
  Fix belongsToMany example
related only needs to be on the model
fixing model.clone's relations
making the context of eagerFetch a bit less ambiguous
defaults: true option to update with defaults, otherwise defaults only used on save
working on the previousAttributes imp.
using Object.create(null) for user defined hashes
some Object.create(null)'s
mistake in docs, fixes #17
finishing up previous attributes pieces
0.1.3
Merge branch 'master' into gh-pages

* master:
  0.1.3
  finishing up previous attributes pieces
  some Object.create(null)'s
  using Object.create(null) for user defined hashes
  working on the previousAttributes imp.
  defaults: true option to update with defaults, otherwise defaults only used on save
  making the context of eagerFetch a bit less ambiguous
  fixing model.clone's relations
  related only needs to be on the model
removing aliases for Events
fixing issue with model idAttribute, 0.1.4
0.1.4
Merge branch 'master' into gh-pages

* master:
  0.1.4
  fixing issue with model idAttribute, 0.1.4
  removing aliases for Events
fixing version #