title: What to do when I remake model
body: <p>When I want to remake a model, I run <code>rails d model X</code> and run <code>rails g model X ...</code>. However, when I run <code>rake db:migrate</code>, it fails and console says 'table X already exists'.</p>
  
  <p>I found that it works if I manually rewrite schema.rb.</p>
  
  <p>Is this a right way? Are there other things to do(ex. to rewrite) when I destroy and create same model?</p>