Allowing TS::Comment attachments to be created by a hash.
Allowing TS::Comment attachments to be created by a hash.

There were two possible solutions here:

1. Always require a TS::Attachment object in #attachments=
2. Do the typecasting in #attachments=

I chose solution 2. Solution 2 depends on typecasting in the .parse
method -- which is fine. It also depends on typecasting in .new. This
would cause duplication.

So I chose the ladder, and do the typecasting everywhere. In .new, in
.parse, and any time #attachments= is called.

zendesk/ticket_sharing