I have a current need for allowing both admin configurable global settings as well as per-user configurable settings within a Rails 3 app.
Are there any gems or best
As always right after asking for help my search bears fruit. Found Georg Ledermann's fork of rails-settings that looks like it will do just what I need.
For rails 4, if you are using postgresql, you can use HStore, which is just like a serializable attribute, but you do SQL queries with it.
For rails 3, you can use activerecord-postgres-hstore gem.
May also want to look at https://github.com/railsjedi/rails_config. Amongst it's many features:
Not sure I would look for a library for this function.
For global settings, I would create a config/application.yml file and read it in environment.rb and set it to an APP_CONFIG global. Then, I would override those settings on a per-user basis by adding a text column to the user table with json-encoded settings hash. Add a method to the user model that grabs APP_CONFIG and does a deep merge on the decoded user settings.
Another option would be to create a settings table, with a user_id column, and columns for each setting. One row with a null user_id would represent global settings. If a row exists for the current user, any non-nil values would override the global settings row.