title: Rals concatenate attribute in active record
body: <p>This query selects a printer (record in db)</p>
  
  <pre><code>@printer_receipt = Printer.where(print_receipts: 1)
  </code></pre>
  
  <p>I want to concatenate the attribute </p>
  
  <pre><code>@printer_receipt.printer_position
  </code></pre>
  
  <p>to:</p>
  
  <pre><code>printer = CupsPrinter.new(printers)
  </code></pre>
  
  <p>to select correct printer to execute a job.</p>
  
  <p>To have something like:</p>
  
  <pre><code>printer = CupsPrinter.new(printers.@printer_receipt.printer_position)
  </code></pre>
  
  <p>which should return:</p>
  
  <pre><code>  printer = CupsPrinter.new(printers.first)
  </code></pre>
  
  <p>assuming </p>
  
  <pre><code>@printer_receipt.printer_position = first
  </code></pre>
  
  <p>What is the correct syntax?</p>