Add a second elasticache connection for dual write

[joaojunceira-zendesk]

Description

• Add second elasticache connection for dual write;

References

• Github issue:

Risks

• High | Medium | Low : How might failures be experienced? All code changes
  carry a minimum of risk of Low, and None should be a rare exception.
• Rollback:

[sergionoviello]

LGTM