Allow custom rails generators to pass in their own binding to Create command so that the corresponding erb templates get rendered with the proper binding [#1493 state:resolved]

railties/lib/rails_generator/commands.rb

@@ -294,7 +294,7 @@ HELP
           file(relative_source, relative_destination, template_options) do |file|
             # Evaluate any assignments in a temporary, throwaway binding.
             vars = template_options[:assigns] || {}
-            b = binding
+            b = template_options[:binding] || binding
             vars.each { |k,v| eval "#{k} = vars[:#{k}] || vars['#{k}']", b }
 
             # Render the source file with the temporary binding.