text: const mongoose = require('mongoose');
  const Schema = mongoose.Schema;
  const timestamps = require('mongoose-timestamp');
  
  const pictureSchema = new Schema({
      music : { type : Schema.Types.ObjectId , ref : 'Music'},
      title: { type:String , required: true},
      body: { type: String , required: true },
      size: { type: Number , required: true},
      pictureUrl: { type: String }
  });
  
  pictureSchema.plugin(timestamps);
  module.exports = mongoose.model('Picture' , pictureSchema);