code: function addConstraintsForForeignKeys (bookshelfModel, baseQuery) {
    if (typeof baseQuery === 'undefined') {
      return
    }
    
    _.forEach(baseQuery({params: {}, payload: {}}), function(v, k) {
      const value = bookshelfModel.prototype.schema[k]
      if (typeof value === 'undefined') {
        bookshelfModel.prototype.schema[k] = Joi.any().required()
      }
      else if (value.isJoi) {
        bookshelfModel.prototype.schema[k] = bookshelfModel.prototype.schema[k].required()
      }
    })
  }
docs: Adds required() validation constraints to all the bookshelfModel's foreign keys, as defined in baseQuery.