replace autoloads with requires in sorcery.rb
Replace `migrations` generator option with `only-submodules`

Gnerator has an option `--migrations` that actually does not do what its name
says. It also changes user model and initializer. The real change it does is
that if it's provided, no core files are copied (user model is not generated,
core migrations are not copied).

Therefore the proper name for this option is `--only-submodules`.
THe previous option was deprecated and should be removed in v0.9.0.
Make @user.setup_activation a public method

Curretly @user.setup_activation is a protected method of User class,
but supposedly it is useful to make the method callable whenever and
from wherever you want.
For example, you can require users to re-activate their accounts when
they change registered emails.
Update README.md
Merge pull request #574 from arnvald/changes_in_generator_options

Replace `migrations` generator option with `only-submodules`
Merge pull request #573 from arnvald/remove_autoloads

replace autoloads with requires in sorcery.rb
Update CHANGELOG.md
Merge pull request #576 from iTakeshi/publicate_setup_activation

Make @user.setup_activation a public method
Proper file naming for DataMapper (datamapper -> data_mapper)

The problem with previous naming is that if we call `"datamapper".classify` it
will return `Datamapper` instead of `DataMapper`.

As I'm trying to get rid of coupling Sorcery with ORM adapters, this has become
an issue in my attempts to implement generic adapter setup
Merge pull request #578 from arnvald/data_mapper_file_naming

Proper file naming for DataMapper (datamapper -> data_mapper)
Update #increment in Mongoid to allow 3.x and 4.x

The syntax of increment method changed from 3.x to 4.x. This commit makes sure
it will work in both of them
Test different Mongoid versions

We support Mongoid 2, 3 and we're aiming to support Mongoid 4.
Changes in gemfiles allow us to check all of them (but not all Rails-Mongoid
versions combinations!)
Fix gemfiles to test properly agains Mongoid 4 and Rails 4 and 4.1
add gemfile for Mongoid 3