text: const mongoose = require('mongoose');
  const tz = require('mongoose-timezone');
  
  const inventorySchema = new mongoose.Schema({
    quantity: {
      type: Number,
      required: true,
      default: 0,
    },
    sales: {
      type: Number,
      default: 0,
    },
    returns: {
      type: Number,
      default: 0,
    },
    leftOver: {
      type: Number,
      default: 0,
    },
    product: {
      type: mongoose.Schema.Types.ObjectId,
      ref: 'Product',
    },
  });
  
  inventorySchema.plugin(tz);
  module.exports = mongoose.model('Inventory', inventorySchema);
  