Log Message:
Update databases/ruby-sequel to 1.4.0.  Changes from version 1.3 include:

+ Add patch-aa and patch-ab which are changes pulled from upstream to
  allow the creation of new records that don't have a primary key when
  the cache is on.

* Merge ``sequel_model'' into ``sequel''.
* Eager loading for all types of associations.
* One-to-many associations now populate the corresponding many-to-one
  instance variable (even when eagerly loaded).
* ActiveRecord style has_many :through associations are now supported
  via many_to_many.  many_to_many will no longer select the entire result
  set, just the columns of the associated table (and not the join table),
  so it works for both has_and_belongs_to_many (simple join table) and
  has_many :through (join table model) scenarios.