Remove required keys, to support IAM roles

[kkumler]

Not specifying the access key id and secret access key to allow aws-sdk to load from the EC2 instance profile.
Fixes #29

[tomdale]

Similarly, I'd like to be able to specify a profile I have saved with the AWS CLI in lieu of the credentials.

[ghedamat]

thanks @kkumler !

just one tiny thing, maybe clarify in the readme that the secret is to be used in combo with the access key and not with the IAM role? I know it seems obvious but it's probably better to be explicit just in case.

@tomdale shall we do what you suggest as part of a separate PR? (I assume aws-sdk will allow us to support your use case)

[kkumler]

@ghedamat Sure, I'll update the readme a bit more for that.

I'll keep this PR to just this change, but I could refactor things a bit and include functionality for all authentication options more cleanly, in a separate PR.

[ghedamat]

@kkumler sounds like a plan!

[tomdale]

@ghedamat It looks like the AWS SDK respects the AWS_PROFILE environment variable, so long as ember-cli-deploy-s3 isn't manually overriding anything: http://docs.aws.amazon.com/AWSJavaScriptSDK/guide/node-configuring.html#Using_Profiles_with_the_SDK

[kkumler]

Yep. I was thinking that would cover most everyone's use case. It'll be
part of the readme update here.

Kris

[lukemelia]

👍 looks good!

[ghedamat]

thanks @kkumler !