I have specified `firstname` and `lastname` MongoDB fields to **not** be unique, but i am still running into an issue that I cannot say non-unique firstnames and lastnames. 

How do I specify to MongoDB it is okay to have duplicate of `firstname` and `lastname`?

```
extend type Mutation {
    signUp(
      firstname: String!
      lastname: String!
      email: String!
      password: String!
    ): Token!

...

const userSchema = new mongoose.Schema(
  {
    email: {
      type: String,
      unique: true,
      required: true,
      validate: [isEmail, 'Not a valid email'],
    },
    firstname: {
      type: String,
      unique: false
    },
    lastname: {
      type: String,
      unique: false
    },
    password: {
      type: String,
      required: true,
      minlength: 7,
      maxlength: 42,
    },
  },
  {
    timestamps: true,
  },
);

```

Error:

```
E11000 duplicate key error collection: testDb.users index: firstname_1 dup key: { firstname: "Test" }

```