add the database gem

railties/lib/rails/generators/app_base.rb

@@ -121,11 +121,9 @@ module Rails
       end
 
       def database_gemfile_entry
-        options[:skip_active_record] ? "" :
-          <<-GEMFILE.strip_heredoc
-            # Use #{options[:database]} as the database for Active Record
-            gem '#{gem_for_database}'
-          GEMFILE
+        return [] if options[:skip_active_record]
+        gem = GemfileGem.new gem_for_database, "Use #{options[:database]} as the database for Active Record"
+        return [gem]
       end
 
       def include_all_railties?

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -163,7 +163,7 @@ module Rails
       end
 
       def gemfile_gems
-        rails_gemfile_entry
+        rails_gemfile_entry + database_gemfile_entry
       end
 
       public_task :set_default_accessors!

railties/lib/rails/generators/rails/app/templates/Gemfile

@@ -2,7 +2,10 @@ source 'https://rubygems.org'
 
 <% max_width = gemfile_gems.map { |g| g.name.length }.max -%>
 <% gemfile_gems.each do |gem| -%>
-<%= gem.comment -%>
+<% if gem.comment -%>
+
+# <%= gem.comment %>
+<% end -%>
 <% if gem.version -%>
 gem '<%= gem.name %>',<%= gem.padding(max_width) %>'<%= gem.version %>'
 <% elsif gem.path -%>
@@ -14,8 +17,6 @@ gem '<%= gem.name %>'
 <% end -%>
 <% end -%>
 
-<%= database_gemfile_entry -%>
-
 <%= assets_gemfile_entry %>
 <%= javascript_gemfile_entry -%>