Add comments about author attribute to stub spec.

Fixes https://github.com/CocoaPods/Specs/pull/84#commits-pushed-45cb459.

lib/cocoapods/command/spec.rb

@@ -42,7 +42,14 @@ module Pod
             s.version  = '1.0.0'
             s.summary  = 'A short description of #{@name}.'
             s.homepage = 'http://EXAMPLE/#{@name}'
-            s.author   = { '#{author}' => '#{email}' }
+
+            # Specify the authors of the library, with email addresses. You can often find
+            # the email addresses of the authors by using the SCM log. E.g. $ git log
+            #
+            s.author   = { '#{author}' => '#{email}', 'other author', => 'and email address' }
+            # If absolutely no email addresses are available, then you can use this form instead.
+            #
+            # s.author   = '#{author}'
 
             # Specify the location from where the source should be retreived.
             #