title: The PGconn, PGresult, and PGError constants are deprecated on Heroku and Rails
body: <p>I reset the database on Heroku in the database setting and ran <code>heroku run rake db:migrate</code>. Although it created all the data tables with correct columns per local database, it does not migrate any existing local data. Heroku database is just empty. In the past I ran the above code and worked fine but this time got stuck as shown below:</p>
  
  <pre><code>mac-a:skiny ran$ heroku run bundle exec rake db:migrate
  Running bundle exec rake db:migrate on ⬢ blooming-citadel-66205... up, run.3076 (Hobby)
  The PGconn, PGresult, and PGError constants are deprecated, and will be
  removed as of version 1.0.
  
  You should use PG::Connection, PG::Result, and PG::Error instead, respectively.
  
  Called from /app/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:240:in `load_dependency'
  ActiveRecord::SchemaMigration Load (1.2ms)  SELECT "schema_migrations".* FROM "schema_migrations"
  </code></pre>
  
  <p>As a note, I quit mac terminal while running <code>heroku run rake db:reset</code> and maybe there is some internal error...</p>