text: const { Schema , model } = require('mongoose');
  
  const UserSchema = new Schema({
      username: {
          type: String,
          unique: true,
          required: true,
          trim: true
      },
      email: {
          type: String,
          unique: true,
          required: true,
          match: [/.+@.+\..+/, 'Enter a valid email.']
      },
      thoughts: [
          {
              type: Schema.Types.ObjectId,
              ref: 'Thought'
          }
      ],
      friends: [
          {
              type: Schema.Types.ObjectId,
              ref: 'User'
          }
      ]
  },
  {
      toJSON: {
          virtuals: true,
          getters: true
      },
      id: false
  });
  
  const User = model('User', UserSchema);
  
  UserSchema.virtual('friendCount').get(function() {
      return this.friends.length;
  });
  
  module.exports = User;