move custom fields into its own concern
Add CustomFields to Post, Category and Group
fix double save missing error by using copy not actual reference
Add Custom Fields on Topics
Add Support for Arrays to CustomFields
Move Concern from lib into app/models. refs #2279
use more explicit naming to prevent name clashes. fixes build.
Ensure Reload reloads custom_fields, too
Merge pull request #2297 from ligthyear/custom-fields

Custom fields for Topic, Category, Post and Group