定义Schema时不可为空约束应该是 required，而不是 require吧

[guchenhui]

const UserSchema = new Schema({
name: {
type: String,
unique: true, // 不可重复约束
required: true // 不可为空约束
},
password: {
type: String,
required: true
},
token: {
type: String
}
});