Only load db/schema.rb if it exists; otherwise, display a message to …

…run db:migrate or remove active_record in environment.rb.

[#3012 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

railties/lib/tasks/databases.rake

@@ -256,7 +256,11 @@ namespace :db do
     desc "Load a schema.rb file into the database"
     task :load => :environment do
       file = ENV['SCHEMA'] || "#{RAILS_ROOT}/db/schema.rb"
-      load(file)
+      if File.exists?(file)
+        load(file)
+      else
+        abort %{#{file} doesn't exist yet. Run "rake db:migrate" to create it then try again. If you do not intend to use a database, you should instead alter #{RAILS_ROOT}/config/environment.rb to prevent active_record from loading: config.frameworks -= [ :active_record ]}
+      end
     end
   end