title: Adding ActiveRecord on top of a Rails + Mongoid install
body: <p>I have an existing project with Rails 5.2 and Mongoid 7, I had previously disabled all activerecord-related modules.</p>
  <p>We are working on some synchronization with business intelligence data warehouses, and I discovered <a href="https://github.com/customink/activerecord-aurora-serverless-adapter" rel="nofollow noreferrer">this gem</a> that seems like a good starting point : I'm planning to use ActiveRecord with this adapter to easily implement code that will push data to my Amazon Aurora DB for BI purposes.</p>
  <p>I have created a simple model</p>
  <pre><code># model/test.rb
  class Test &lt; ActiveRecord::Base
  end
  </code></pre>
  <p>I have added a database.yml</p>
  <pre><code># config/database.yml
  development:
    adapter: aurora_serverless
    ...
  </code></pre>
  <p>But when I try to do anything with a model it says it could not connect</p>
  <blockquote>
  <p>ActiveRecord::ConnectionNotEstablished: No connection with pool with 'primary' found</p>
  </blockquote>
  <p>Am I missing other things to make ActiveRecord work ? Do I need some additional Railties, etc ? It's as if the database.yml file was not read at all</p>