[ [ { _id: '5990e6d4fce2e705f8d74923',
      fname: 'test',
      lname: 'testerson1',
      username: 'email1@gmail.com',
      __v: 0,
      userid: '5990e6b9fce2e705f8d74922' },
    { _id: '5990e6e6fce2e705f8d74924',
      fname: 'test',
      lname: 'testerson2',
      username: 'email2@gmail.com',
      __v: 0,
      userid: '5990e6b9fce2e705f8d74922' } ],
  [ { _id: '5990e6f7fce2e705f8d74925',
      fname: 'test',
      lname: 'testerson3',
      username: 'email3@gmail.com',
      __v: 0,
      userid: '5990e6b9fce2e705f8d74922' },
    { _id: '5990e707fce2e705f8d74926',
      fname: 'test',
      lname: 'testerson4',
      username: 'email4@gmail.com',
      __v: 0,
      userid: '5990e6b9fce2e705f8d74922' } ] ]

var UserSchema = new mongoose.Schema({
    fname: String,
    lname: String,
    username: String,
    password: String,
    testers: [
        [
            {
                type: mongoose.Schema.Types.ObjectId,
                ref: "Tester"
            }
        ]
    ]
});