deploy.sh generating cf-notify stack with wrong name

[jonlorusso]

deploy.sh is generating a stack with the name cf-notify.

The Usage section of the documentation says to use a --stack-name of cf-notify-$CHANNEL. This causes the following error:

An error occurred (ValidationError) when calling the DescribeStacks operation: Stack with id cf-notify-builds does not exist

In my case, I only need to notify to a single channel so I can simple change the command, but it was still confusing. Others might need the ability to target different channels, in which case deploy.sh should be changed.

[jonlorusso]

#13