code: function acl (schema, options) {
    options = options || {}
  
    // Options
    var aclPath = options.aclPath || 'acl'
      , fields = {}
  
    if (!schema.paths[aclPath]) {
      fields[aclPath] = {
        type: [String]
      , default: ['public']
      }
    }
    schema.add(fields)
    
    schema.method('addAccess', function (key) {
      if (!this.access(key)) {
        this.acl.push(key)
        this.markModified('acl')
      }
      return this
    })
    
    schema.method('removeAccess', function (key) {
      if (this.access(key)) {
        this.acl.splice(this.acl.indexOf(key), 1) 
        this.markModified('acl')
      }
      return this
    })
  
    schema.method('access', function (key, next) {
      var bool = !!~this.acl.indexOf(key)
      next && next(bool)
      return bool
    })
  }
docs: acl --- Plugin