Add flush hooks to automatically create a "code", or "slug" as it's
named in the model, for objects that have slugs.
Add a migration to add uniqueness constraint and to generate default
slugs where needed for the slug field.
Merge branch 'develop' into feature/add_program_code
Upper case the type name on generated slugs and add a '-' between the
type and the generated number.
Merge branch 'develop' into feature/add_program_code
Merge pull request #110 from reciprocity/feature/add_program_code

Add "code" fields by default.