<prompt> Tengeneza API ya RESTful kwa kutumia Node.js na Express inayodhibiti mfumo rahisi wa kuorodhesha. API inapaswa kuauni shughuli za CRUD kwa bidhaa na kategoria, huku kila bidhaa ikiwa ya aina moja. Tumia PostgreSQL kama hifadhidata ya nyuma na uhakikishe uthibitisho sahihi kwa maombi yote yanayoingia.PLINFORMAT  <response>: const express needexpress;const bodyParser needbody-parser;const cors needcors;const Sequelize needsequelize;needdotenv.config; Sanidi unganisho la hifadhidataconst sequelize Sequelize mpyaprocess.env.DB_NAME, process.env.DB_USER, process.env.DB_PASSWORD, mwenyeji: process.env.DB_HOST, lahaja: postgres,;async jaribu subiri sequelize.authenticate; console.logMuunganisho wa hifadhidata umefanikiwa.; kukamata kosa console.errorHaiwezi kuunganisha kwenye hifadhidata:, hitilafu; ; Fafanua muundo wa Bidhaaconst DataTypes needsequelize;const Product sequelize.defineBidhaa, kitambulisho: aina: DataTypes.INTEGER, Msingi muhimu: kweli, AutoIncrement: kweli, , jina: aina: DataTypes.STRING, allowNull: uongo, , maelezo: aina: DataTypes.TEXT, , bei: aina: DataTypes.FLOAT, allowNull: uongo, ,; Bainisha muundo wa KategoriaConst Category sequelize.defineJamii, kitambulisho: aina: DataTypes.INTEGER, Msingi muhimu: kweli, AutoIncrement: kweli, , jina: aina: DataTypes.STRING, allowNull: uongo, ,;Jamii.hasMengiBidhaa;Bidhaa.nizaKitengo; Njia za kuingizaconst productRoutes hitaji.routesproductRoutes;const categoryRoutes need.routescategoryRoutes; Sanidi programu ya Expressconst app express;app.usecors;app.usebodyParser.json;app.useapiproducts, productRoutes;app.useapicategories, kategoriaNjia;const PORT process.env.PORT 3000;app.listenPORT, console.logSeva inafanya kazi kwenye bandari PORT;; 