title: Postgresql not working with ruby on rails on mac os x
body: <p>I just switched to mac, I was previously working on Linux.
  I am trying to use posgresql for my project</p>
  
  <p>When I start the server, it works fine.</p>
  
  <p>Nevertheless when I use rake:db:migrate, it fails saying:
  Please install the postgresql adapter: <code>gem install activerecord-postgresql-adapter</code> (no such file to load -- pg)</p>
  
  <p>I have the gem "pg" installed, and there are no such gem as activerecord-postgresql-adapter.</p>
  
  <p>I find it weird that when I do ./script/server it works, but not when I do rake:db:migrate</p>
  
  <p>Thnaks</p>