title: How store work days of week in db
body: <p>I have <strong>Shop</strong> entity</p>
  
  <p>I need 7 checkboxes to set working days for this shop on frontend</p>
  
  <p>I'm looking for best solution to store values in db.
  The easiest method is to keep 7 boolean fields like "monday?" "tuesday?" ... in db</p>
  
  <p>Can you help me? thanks</p>
  
  <p>PS: it should be searchable (ex. i want all shops working today)</p>
  
  <p>Rails 3, Postgresql 8.4</p>