title: Concat inside rails query conditions
body: <p>I am new to rails.
  I would like to write this SQL query in the rails way :</p>
  
  <pre><code>select * from USER where ((name+' '+firstname) like %search%) or ((firstname+' '+name) like %search%) or (name like %search%)  or (firstname like %search%)
  </code></pre>
  
  <p>How can i do this? </p>