title: Association name conflicts with method in Active Record
body: <p>Hi I am a beginner with rails and setting up a database/model with various associations. </p>
  
  <p>I want my <code>transactions</code> controller to save to the DB both the <code>transactions</code> record and the corresponding <code>subtransactions</code> records (i.e. one row for each subtransaction (e.g. product) in the transaction). </p>
  
  <p>After creating a new table <code>subtransactions</code> (associated with <code>transactions</code>), I got the following exception:</p>
  
  <p><strong>ArgumentError in TransactionsController#create</strong></p>
  
  <pre><code>You tried to define an association named transaction on the model Subtransaction, 
  but this will conflict with a method transaction already defined
  by Active Record. Please choose a different association name.
  </code></pre>
  
  <p>I'm a bit confused about what this tells me, or more specifically where to look for the mistake. Not sure how to find out what method my association is conflicting with.</p>