Configuration of ContentfulModel gem is lost after initialization - ruby-on-rails

Question

Completely new Rails 4.2.3 application. The only changes to the Gemfile have been removal of Spring, addition of dotenv, and the latest contentful_rails and contentful_model gems as published on rubygems.org.
For unknown reasons, the configuration details defined in the initializer are gone by the time the app comes up. It's the same object (same value for ContentfulModel.configuration.object_id) but the values that were previously correct are now nil.
I added an initializer as shown in the README.
$ cat config/initializers/contentful_model.rb
ContentfulModel.configure do |config|
byebug
config.access_token = ENV['CONTENTFUL_ACCESS_TOKEN']
config.preview_access_token = ENV['CONTENTFUL_PREVIEW_ACCESS_TOKEN']
config.space = ENV['CONTENTFUL_SPACE']
# config.options = {
#extra options to send to the Contentful::Client
# }
end
And I defined one model, Category.
$ cat app/models/category.rb
class Category < ContentfulModel::Base
self.content_type_id = "[category content type string]"
end
So here's what happens when I fire up the Rails console:
$ rails c
[1, 9] in /home/trevor/code/chef/www-contentful-rails/config/initializers/contentful_model.rb
1: ContentfulModel.configure do |config|
2: config.access_token = ENV['CONTENTFUL_ACCESS_TOKEN']
3: config.preview_access_token = ENV['CONTENTFUL_PREVIEW_ACCESS_TOKEN']
4: config.space = ENV['CONTENTFUL_SPACE']
5: # config.options = {
6: #extra options to send to the Contentful::Client
7: # }
8: byebug
=> 9: end
(byebug) ContentfulModel.configuration
#<ContentfulModel::Configuration:0x00000005bc7be0 #access_token="[my actual token string]", #entry_mapping={}, #preview_access_token="[my actual preview token string]", #space="[my actual space]">
(byebug) continue
/home/trevor/.rvm/gems/ruby-2.2.2#www-contentful-rails/gems/actionpack-4.2.3/lib/action_dispatch/http/mime_type.rb:163: warning: already initialized constant Mime::JSON
/home/trevor/.rvm/gems/ruby-2.2.2#www-contentful-rails/gems/actionpack-4.2.3/lib/action_dispatch/http/mime_type.rb:163: warning: previous definition of JSON was here
Loading development environment (Rails 4.2.3)
2.2.2 :001 > ContentfulModel.configuration
=> #<ContentfulModel::Configuration:0x00000005bc7be0 #access_token=nil, #entry_mapping={"[category content type string]"=>Category}, #preview_access_token=nil, #space=nil>
2.2.2 :002 >
I've spent a bunch of time sifting the gem source and stepping through the debugger without results. I've posted an issue for the project on GitHub because I haven't been able to identify the source of the problem and I have to assume its within the gem. Any assistance with how to troubleshoot this further would be very welcome!

Answer 1

The solution was to use the undocumented approach required due to changes a few months ago.
The contentful_rails gem requires contentful_model (and vice versa), and the only configuration documentation for contentful_model is in that project's README, describing the approach in my question. Configuration made in this way was then completely wiped when contentful_rails was initialized, which expected the configuration to be done in its own initializer.
So I have deleted config/initializers/contentful_model.rb and now my config/intializers/contents_rails.rb file looks like:
ContentfulRails.configure do |config|
config.authenticate_webhooks = true # false here would allow the webhooks to process without basic auth
config.webhooks_username = ENV['CONTENTFUL_WEBHOOK_USERNAME']
config.webhooks_password = ENV['CONTENTFUL_WEBHOOK_PASSWORD']
config.access_token = ENV['CONTENTFUL_ACCESS_TOKEN']
config.preview_access_token = ENV['CONTENTFUL_PREVIEW_ACCESS_TOKEN']
config.space = ENV['CONTENTFUL_SPACE']
config.contentful_options = {
#extra options to send to the Contentful::Client
}
end
Of note is that config.options is no longer a thing; it's config.contentful_options.