Add support for CollectionAssociation#delete by Fixnum or String

I found the next issue between CollectionAssociation `delete`
and `destroy`.

    class Person < ActiveRecord::Base
      has_many :pets
    end

    person.pets.destroy(1)
    # => OK, returns the destroyed object

    person.pets.destroy("2")
    # => OK, returns the destroyed object

    person.pets.delete(1)
    # => ActiveRecord::AssociationTypeMismatch

    person.pets.delete("2")
    # => ActiveRecord::AssociationTypeMismatch

Adding support for deleting with a fixnum or string like
`destroy` method.

1 files changed, 13 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 8f1f315e42..1a8e233a51 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,18 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Added support to `CollectionAssociation#delete` for passing `fixnum`
+    or `string` values as record ids. This finds the records responding
+    to the `id` and executes delete on them.
+
+        class Person < ActiveRecord::Base
+          has_many :pets
+        end
+
+        person.pets.delete("1") # => [#<Pet id: 1>]
+        person.pets.delete(2, 3) # => [#<Pet id: 2>, #<Pet id: 3>]
+
+    *Francesco Rodriguez*
+
 *   Deprecated most of the 'dynamic finder' methods. All dynamic methods
     except for `find_by_...` and `find_by_...!` are deprecated. Here's
     how you can rewrite the code: