Add table for service instances

[Ladas]

Add table for service instances. We need the service instances
modeled to be able to do service retirement.

[Ladas]

@miq-bot assign @agrare
@miq-bot add_label enhancement

[Ladas]

@gmcculloug @gtanzillo @agrare so we've talked with @syncrou and without this modeled, we are not able to retire the services.

[miq-bot]

Checked commit Ladas@0d9d17d with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
1 file checked, 1 offense detected

db/migrate/20180827083140_create_service_instances_table.rb

• ❗ - Line 12, Col 7 - Style/MethodCallWithArgsParentheses - Use parentheses for method calls with arguments.

[gmcculloug]

@Ladas Totally understand, the current effort we are working on is purely focused on ordering. While we do not have an immediate need for this data I suspect we (or someone) will in the future. Likely, the near future.

[Ladas]

so, do we have better naming than service_instance?

[agrare]

@gmcculloug are you good with the name "service_instances"?

[agrare]

@syncrou what do you think of the name?

[syncrou]

I think the referencing foreign key ( service_offering_id ) is the one piece that saves us from getting very confused with service_templates, service which have nothing to do with service_offerings, service_instances. LGTM 👍

[Ladas]

@bdunne can you add the API also for service_instances ?