Merge pull request activeadmin#4889 from Neodelf/master

Remove empty rows generated in migration

Author: Fivell

Diff for: lib/generators/active_admin/install/templates/migrations/create_active_admin_comments.rb.erb

@@ -1,8 +1,7 @@
 <%
 parent_class = ActiveRecord::Migration
 parent_class = parent_class[5.0] if Rails::VERSION::MAJOR >= 5
-%>
-
+-%>
 class CreateActiveAdminComments < <%= parent_class.to_s %>
   def self.up
     create_table :active_admin_comments do |t|