Fix typo in prod env check

* The ActiveSupport::StringInquirer is just a fancy string comparison,
  so the strings have to match 😆. The correct environment name
  is "production".

h/t @xdmx

Author: iamvery

lib/jsonapi/exceptions.rb

@@ -10,7 +10,7 @@ def initialize(exception)
       end
 
       def errors
-        unless Rails.env.prod?
+        unless Rails.env.production?
           meta = Hash.new
           meta[:exception] = exception.message
           meta[:backtrace] = exception.backtrace