postgresql_role: Add roles attribute.

[cyrilgdn]

This allows to grant roles to the role we are managing.

Example:

resource postgresql_role "test_group" {
  name = "test_group"
}

resource postgresql_role "test_role" {
  name  = "test_role"
  roles = ["${postgresql_role.test_group.name}"]
}

Fix #21

This probably conflicts with #23

[evgmoskalenko]

@cyrilgdn, Hello, tell me please, when the release is expected?

[cyrilgdn]

@evgmoskalenko I'm currently looking for reviews for all my PRs, as soon as they get merged I'll try to create a new release.
My goal is to do it as soon as possible but unfortunately I can't give you a date.
However, you can watch the repository in the new "Releases only" mode so you'll be notified

[multani]

@cyrilgdn I tried the code from this PR, it seems to work as advertised, the tests look good to me and I tried to make it break without success :)

Hopefully this can get merged and released really soon!

As a side node: As said previously, while testing this PR, I saw lot of connections/disconnections on the PostgreSQL server, while applying this type of change - it's not specifically due to this patch though but I guess this could be looked into.

[cyrilgdn]

Thanks @multani , I've just added the documentation for the website (which I forgot).

Good remark for the connections number, it's the case for multiple resources, I'll try to enhance these behaviors in the future.

[ixalon]

@cyrilgdn - this feature is exactly what I was looking for today (to grant the rds_iam role to enable IAM authentication when running on AWS RDS). Thank you!

Any idea when you’ll be able to roll a release with this feature?

[cyrilgdn]

@ixalon I'll try to release a version this week

[jaypz]

@cyrilgdn
Any update on when to expect this release? Thanks!

[cyrilgdn]

@jaypz Yes sorry, didn't take the time to do it as announced .

I've just asked to create the 0.4.0 release. It should be good for tomorrow (except if any troubles with the release process).
I'll let you know here when it's good. You can also watch (if it's not already the case) this repository in the "Releases only" mode to be alerted as soon as it's released.

[cyrilgdn]

@jaypz @ixalon Actually it's already released 👍 (thanks to Terraform developers which have been very fast !)