associate_db.js

const db = require('../models')

db.sequelize.sync().then(function () {
  // Require our JSON
  const cardJson = require('../.data/cards.json').cards

  // For Each card, let's associate it!
  cardJson.forEach(async card => {
    // get the Model for the current card
    const cardModel = await db.Card.findOne({
      where: {
        name: card['name']
      }
    })

    // associate each element
    card.elems.forEach(async el => {
      const elemModel = await db.Element.findOne({
        where: {
          elem: el.toLowerCase()
        }
      })
      await cardModel.addElement(elemModel) // magic!
    })

    // associate each class
    card.classes.forEach(async cl => {
      const classModel = await db.Class.findOne({
        where: {
          class: cl.toLowerCase()
        }
      })
      await cardModel.addClass(classModel)
    })

    const KingdomModel = await db.Kingdom.findOne({
      where: {
        name: card['kingdom'].toLowerCase()
      }
    })
    await cardModel.setKingdom(KingdomModel)
  })
})