sorting example for bolt contenttypes

contenttypes.yml

homepage:
    name: Homepage
    slug: homepage
    singular_name: Homepage feature
    singular_slug: homepagefeature
    fields:
        title:
            type: text
            class: large
            required: true
            pattern: ".{2,255}" # see: http://html5pattern.com/
            error: "The Title field is required, and must contain at least 2 characters"
            group: Text
        sortorder:
            type: integer
            group: meta
            postfix: Items will be displayed from lower order to higher
        subtitle:
            type: text
            class: large
            group: Text
        teaser:
            type: html
            height: 150px
        linktext:
            type: text
            class: large
            group: Text
        linkurl:
            type: text
            class: large
            group: Text
        image:
            type: image
            attrib: title
            extensions: [ gif, jpg, png ]
    default_status: publish
    sort: sortorder