can't use @Index decorator with indexes at the model options

Issue

sequelize-typescript overrides the declarated model option indexes with the decorated indexes.
This is due to a misbehaviour in

sequelize-typescript/src/sequelize/sequelize/sequelize.ts

Line 98 in 8ded61a

...modelOptions,

Versions

sequelize-typescript: 2.1.6

Issue type

bug report

Related code

@Table({
    indexes: [
        {
            unique: true,
            fields: ["email"],
            name: "another_unique_email"
        }
    ]
})
export class Admin extends Model {
    /**
     * User email address.
     */
    @AllowNull(false)
    @Unique({
        name: "unique_email"
    })
    declare public email: string;
}

I've submitted a PR that seems to fix the initial issue, but I've found another issue.
indexArray isn't including @unique indexes.

@Table({
    indexes: [
        {
            unique: true,
            fields: ["name", "email"],
            name: "example_composite_unique_index"
        }
    ]
})
export class Admin extends Model {
     /**
     * User full name.
     */
    @Unique("unique_admin_name")
    @Column(DataType.STRING(256))
    declare public name: string;

    /**
     * User email address.
     */
    @AllowNull(false)
    @Index("admin_email")
    declare public email: string;
}

This results in the following indexesArray:

[
  { name: 'admin_email', fields: [ [Object] ], type: '', parser: null }
]

Wow, this is actually not closed, I've fixed it internally and just linked this issue internally for us to know about it.