Update documentation on Redis for connection URI

[mheadd]

The new AWS Elasticache Redis service may require client applications to use a modified connection URI that uses the rediss:// scheme. When looking at the connection URI in VCAP_SERVICES, it will show as redis:// and some client apps and frameworks may require rediss://. Our documentation should reflect this to assist partners using these apps or frameworks.

[ccostino]

Just to clarify on this a bit more, even though VCAP_SERVICES will report back a URI that is redis:// it will still actually use rediss:// when it's defined?

Do we know if this this an issue with how the information is reported from the broker, somewhere else, or should be investigated?

[mheadd]

That's a good question. You could certainly use the credentials in a different way, without the URL, and our docs show how to do that. I think the issue arises when the app or framework requires the URI to connect, not the hostname, port and password.

[ccostino]

Ah, and this could be problematic if it's more than just a display issue when looking at what's in VCAP_SERVICES - if the URI is actually returned as just redis:// all the time, even if it's defined and intended to be rediss://, that would break the app/framework in the case of the whole URI being required.