async addFixturesForModel(modelFixture, options = {}) {
        // Clone the fixtures as they get changed in this function.
        // The initial blog posts will be added a `published_at` property, which
        // would change the fixturesHash.
        modelFixture = _.cloneDeep(modelFixture);
        // The Post model fixtures need a `published_at` date, where at least the seconds
        // are different, otherwise `prev_post` and `next_post` helpers won't work with
        // them.
        if (modelFixture.name === 'Post') {
            _.forEach(modelFixture.entries, (post, index) => {
                if (!post.published_at) {
                    post.published_at = moment().add(index, 'seconds');
                }
            });
        }

        const results = await sequence(modelFixture.entries.map(entry => async () => {
            let data = {};

            // CASE: if id is specified, only query by id
            if (entry.id) {
                data.id = entry.id;
            } else if (entry.slug) {
                data.slug = entry.slug;
            } else {
                data = _.cloneDeep(entry);
            }

            if (modelFixture.name === 'Post') {
                data.status = 'all';
            }

            const found = await models[modelFixture.name].findOne(data, options);
            if (!found) {
                return models[modelFixture.name].add(entry, options);
            }
        }));

        return {expected: modelFixture.entries.length, done: _.compact(results).length};
    }
### Add Fixtures for Model
Takes a model fixture, with a name and some entries and processes these
into a sequence of promises to get each fixture added.

@param {{name, entries}} modelFixture
@returns {Promise<any>}