title: Arel: How to cleanly join multiple conditions with OR?
body: <p>In my Rails app, I loop through an array to create a list of conditions that must be joined by OR. Below is the basic flow of how I currently do so.</p>
  
  <pre><code>conditions = nil
  set.each do |value|
    condition = value.to_condition
    conditions = conditions ? conditions.or(condition) : condition
  end
  </code></pre>
  
  <p>Obviously, it's not beautiful, but I still don't fully know my way around Arel. Does it offer any better way of OR-joining a set of dynamically-generated conditions?</p>