gistfile1.rb

#commit model
class Commit < ActiveRecord::Base
  # 1) We don't need a provider based Commit subclass, a String field
  # should be enough. In case, we can associate a Provider model
  # (1 to 1 relation) that represents a specific provider
  
  # 2) we might want to use commit IDs, then build the commit URL at runtime
  # (perhaps an URL template specific to the provider should be specified in Provider model)
  # this shuould prevent eventual URL changes by providers :-)
  attr_accessible :commit_url, :author, :commit_message, :provider
end 

#story model 
class Story < ActiveRecord::Base
  has_many :notes
  has_many :commits
end

#view

# I'd split notes and commits because they should be two separate contexts
# In case, we can merge them in a unique Array and do a sort by timestamp, so
# they can appear mixed with proper ordering
<% story.notes.each do |note| %>
   <%= render partial: :note %>
<% end %>

<% story.commits.each do |commit| %>
   <%= render partial: commit.provider %>
<% end %>