Use Module#prepend instead of alias chaining

Now that we no longer support ruby 1.9.3, the loveliness of
Module#prepend is at our disposal!

test/dummy/app/models/song.rb

@@ -1,4 +1,21 @@
-# Example from 'Overwriting default accessors' in ActiveRecord::Base.
+module OverrideSongAttributesTheRails4Way
+  def attributes
+    if name
+      super.merge(name: name)
+    else
+      super
+    end
+  end
+
+  def changed_attributes
+    if name
+      super.merge(name: name)
+    else
+      super
+    end
+  end
+end
+
 class Song < ActiveRecord::Base
   has_paper_trail
 
@@ -15,32 +32,6 @@ class Song < ActiveRecord::Base
     attribute :name, :string
   else
     attr_accessor :name
-
+    prepend OverrideSongAttributesTheRails4Way
-    # override attributes hashes like some libraries do
-    def attributes_with_name
-      if name
-        attributes_without_name.merge(name: name)
-      else
-        attributes_without_name
-      end
-    end
-
-    # `alias_method_chain` is deprecated in rails 5, but we cannot use the
-    # suggested replacement, `Module#prepend`, because we still support ruby 1.9.
-    alias attributes_without_name attributes
-    alias attributes attributes_with_name
-
-    def changed_attributes_with_name
-      if name
-        changed_attributes_without_name.merge(name: name)
-      else
-        changed_attributes_without_name
-      end
-    end
-
-    # `alias_method_chain` is deprecated in rails 5, but we cannot use the
-    # suggested replacement, `Module#prepend`, because we still support ruby 1.9.
-    alias changed_attributes_without_name changed_attributes
-    alias changed_attributes changed_attributes_with_name
   end
 end