title: what's the difference between create and create! in rails
body: <p>for seeding some data using Active Record, I am using <code>Product.create ***:***, ***,***</code></p>
  
  <p>I found it can successfully seed the data into the table.</p>
  
  <p>Someone told me I should use <code>Product.create! ***:***, ***,***</code> is there any difference? Why I should use create!? Is this a must?</p>