Log Message:
Update ruby-will-paginate to 3.1.0.

* Rails 5.0 support

* Drop support for old Active Record finder params to paginate():

    # now unsupported:
    User.paginate(:page => 1, :order => 'created_at DESC', :conditions \ 
=> ...)

    # convert to Arel syntax instead:
    User.order('created_at DESC').where(...).paginate(:page => 1)
    # or, even better:
    User.order('created_at DESC').where(...).page(1)

* Add support for pagination with Mongoid