text: var mongoose = require('mongoose');
  var Schema= mongoose.Schema;
  
  
  var vehicleSchema = new mongoose.Schema({
    _id : {
      type: String,
      required: true,
      unique: true
    },
    make: {
      type: String,
      required: true
    },
    year: {
      type: Number,
      required: true
    },
    model: {
      type: String,
      required: true
    }
  });
  
  module.exports = mongoose.model('vehicle', vehicleSchema);
  
  