Cross-account access

[andrykonchin]

As a way to work with tables in other AWS accounts it might be useful to use a table ARN instead of just a table name (namespace + table name in Dynamoid terms).

Implement a way to specify a table ARN, e.g. in the following way:

class User
  include Dynamoid::Document

  table arn: 'arn:aws:dynamodb:*:*:table/users'
end

Related discussions:

• Feature: Add multi-config #918 (comment)
• Support multiple configurations #403 (comment)
• am I able to configure API calls to use different set of AWS credentials, table, with the same model? #831 (comment)

Related documentation:

• https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/configure-cross-account-access-to-amazon-dynamodb.html
• https://docs.aws.amazon.com/IAM/latest/UserGuide/reference-arns.html
• https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_dynamodb_specific-table.html