Importing to intermediate table with insert select query after import completion

ActiveAdmin.register Post  do
        active_admin_import validate: false,
            csv_options: {col_sep: ";" },
            resource_class: ImportedPost ,  # we import data into another resource
            before_import: proc{ ImportedPost.delete_all },
            after_import: proc{
                Post.transaction do
                    Post.delete_all
                    Post.connection.execute("INSERT INTO posts (SELECT * FROM imported_posts)")
                end
            },
            back: proc { config.namespace.resource_for(Post).route_collection_path } # redirect to post index
    end