Improve "rake gems:install" handling, within the constraints of chef's callback order

recipes/rails.rb

@@ -169,7 +169,7 @@ deploy_revision app['id'] do
   user app['owner']
   group app['group']
   deploy_to app['deploy_to']
-  environment({'RAILS_ENV' => node.app_environment})
+  environment 'RAILS_ENV' => node.app_environment
   action app['force'][node.app_environment] ? :force_deploy : :deploy
   ssh_wrapper "#{app['deploy_to']}/deploy-ssh-wrapper" if app['deploy_key']
   if app['migrate'][node.app_environment] && node[:apps][app['id']][node.app_environment][:run_migrations]
@@ -187,15 +187,24 @@ deploy_revision app['id'] do
     if app['gems'].has_key?('bundler')
       execute "bundle install" do
         ignore_failure true
+        cwd release_path
       end
     elsif app['gems'].has_key?('bundler08')
       execute "gem bundle" do
         ignore_failure true
+        cwd release_path
       end
 
     elsif node.app_environment && app['databases'].has_key?(node.app_environment)
-      execute "rake gems:install" do
+      # chef runs before_migrate, then symlink_before_migrate symlinks, then migrations,
+      # yet our before_migrate needs database.yml to exist (and must complete before
+      # migrations).
+      #
+      # maybe worth doing run_symlinks_before_migrate before before_migrate callbacks,
+      # or an add'l callback.
+      execute "(ln -s ../../../shared/database.yml config/ && rake gems:install); rm config/database.yml" do
         ignore_failure true
+        cwd release_path
       end
     end
   end