Add schema for background

[bmorris3]

spacetelescope/romancal#687 implements sky matching for romancal, and updates a (temporary) "background" dictionary in ImageModel.meta. The dict currently has three keys:

• level (astropy.units.Quantity)
• subtracted (bool)
• method (str)

method can have the options defined by the spec:

option('local', 'global', 'match', 'global+match', default='match')

This should be implemented with a schema in rad.

[ddavis-stsci]

changes merged.

[braingram]

I'm failing to find a background schema. @ddavis-stsci would you help me locate which schema defines this attribute?

[braingram]

Per a conversation with @schlafly at the moment background does not have a schema and it's uncertain if it will get one (since it's optional). I'll try to update this issue if I learn more.

[stscijgbot-rstdms]

This issue is tracked on JIRA as RAD-172.

[stscijgbot-rstdms]

Comment by Paul Huwe on JIRA:

The schema is added in PR-432: #432

 

[stscijgbot-rstdms]

Comment by Paul Huwe on JIRA:

PR approved and merged.