水线,尝试创建一对多关联时出错

我有这些模型:

// Material.js

module.exports = {
attributes: {

    name: {
        type: 'string',
        required: true
    },
    source_info: {
        type: 'string',
        required: true
    },
    category: { model: 'category_mat' }
}
};

和:

// Category_Mat.js

module.exports = {
attributes: {
    name: {
      type: 'string',
      required: true
    },
    material:{
        collection: 'material',
        via: 'category'
    }
},
};

但是当我运行应用程序时,我收到此错误:

/usr/local/lib/node_modules/sails/node_modules/waterline/node_modules/waterline-schema/lib/waterline-schema/foreignKeys.js:82
throw new Error('Trying to access a collection ' + collection + ' that is 
      ^

Error: Trying to access a collection category_mat that is not defined.

at ForeignKeys.findPrimaryKey (/usr/local/lib/node_modules/sails/node_modules/waterline/node_modules/waterline-schema/lib/waterline-schema/foreignKeys.js:82:11)
at ForeignKeys.replaceKeys (/usr/local/lib/node_modules/sails/node_modules/waterline/node_modules/waterline-schema/lib/waterline-schema/foreignKeys.js:53:27)
at new ForeignKeys (/usr/local/lib/node_modules/sails/node_modules/waterline/node_modules/waterline-schema/lib/waterline-schema/foreignKeys.js:30:10)
at new module.exports (/usr/local/lib/node_modules/sails/node_modules/waterline/node_modules/waterline-schema/lib/waterline-schema.js:30:17)
at Waterline.initialize (/usr/local/lib/node_modules/sails/node_modules/waterline/lib/waterline.js:106:17)
at buildORM (/usr/local/lib/node_modules/sails/lib/hooks/orm/build-orm.js:48:15)
at Array.async.auto.instantiatedCollections [as 1] (/usr/local/lib/node_modules/sails/lib/hooks/orm/index.js:191:11)
at listener (/usr/local/lib/node_modules/sails/node_modules/async/lib/async.js:465:46)
at /usr/local/lib/node_modules/sails/node_modules/async/lib/async.js:419:17
at Array.forEach (native)

我使用此文档作为参考:http: //sailsjs.org/#/documentation/concepts/ORM/Associations/OnetoMany.html

所以我不知道我错过了什么,或者是否有我必须做的配置...任何帮助？