fixes not seeing changes to the type of a field

Author: burnt43

lib/mini_record/auto_schema.rb

@@ -239,7 +239,7 @@ def field_attr_changes(field_name)
         # Next, iterate through our extended attributes, looking for any differences
         # This catches stuff like :null, :precision, etc
         # Ignore junk attributes that different versions of Rails include
-        [:name, :limit, :precision, :scale, :default, :null].each do |att|
+        [:name, :limit, :precision, :scale, :default, :null, :type].each do |att|
           value = fields[field][att]
           value = true if att == :null && value.nil?