Issue type:

[X] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[X] postgres
[ ] cockroachdb
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ ] latest
[ ] @next
[X] 0.2.25 (latest at the time of reporting this)

Steps to reproduce or a small repository showing the problem:

1. Create a materialized view with index

@ViewEntity({
  expression:
  `SELECT ...`,
  materialized: true,
})
export class UserTotal {
  @ViewColumn()
  @Index()
  userId!: string;

  ...
}

2. Run typeorm migration:generate

3. Check the migration file. It's missing CREATE INDEX query.