**API** client can see **memory** used for **builds**

[sethboyles]

Context

** This should be done alongside https://www.pivotaltracker.com/story/show/177103073**

Follow up to https://www.pivotaltracker.com/story/show/174473957.

Builds currently support staging_memory_in_mb and staging_disk_in_mb fields which override the memory and disk used to stage the application. These are useful in some cases where an app requires more resources to stage than it needs to run. However, these fields are currently write-only, so API clients can't tell how much memory/disk was used and it is difficult to discover these fields in the first place (especially since we didn't have documentation for them).

Our objective is to always display how much memory/disk a build will use/has used on the build object.

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Acceptance Criteria

Default Memory

Given an app with a web process
And the web process is scaled to 1024 memory_in_mb
When I create a build for the app
Then that build's staging_memory_in_mb should display 1024

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Override Memory

Given an app with a web process
And the web process is scaled to 1024 memory_in_mb
When I create a build for the app
And I specify staging_memory_in_mb is 2048 on the build
Then that build's staging_memory_in_mb should display 2048

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Minimum Memory

Given an app with a web process
And the web process is scaled to 1024 memory_in_mb
And the system minimum staging memory is 2048
When I create a build for the app
And I specify staging_memory_in_mb is 1024 on the build
Then that build's staging_memory_in_mb should display 2048

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✍️Document Staging Memory 📝

Given browsing the v3 API docs
When I view the builds resource
Then there is documentation for the staging_memory_in_mb field
And it appears in the examples

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Notes:

• No need to backfill data for old builds. Happy to chat about any other migration concerns.

[sethboyles]

migrated from https://www.pivotaltracker.com/story/show/175148968

[sweinstein22]

Docs addressed in 83913d2