title: ER diagram for booking database
body: <p>I'm creating a database for booking apartments app.
  I have a question - it is allowable to keep user's <code>passwords</code> in DB (for example using BCrytp)?
  Another question - where is the best way to keep <code>price</code> if it may vary during several months?
  <img src="https://i.stack.imgur.com/HS4m0.png" alt="ER diagram"></p>