Make rubocop happy.

app/controllers/data_explorer/query_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class DataExplorer::QueryController < ::ApplicationController
   requires_plugin DataExplorer.plugin_name
 
@@ -18,7 +20,7 @@ class DataExplorer::QueryController < ::ApplicationController
       query.name = attributes["name"]
       query.description = attributes["description"]
       query.user_id = Discourse::SYSTEM_USER_ID.to_s
-      queries << query 
+      queries << query
     end
 
     render_serialized queries, DataExplorer::QuerySerializer, root: 'queries'
@@ -48,7 +50,7 @@ class DataExplorer::QueryController < ::ApplicationController
         queries = DataExplorer::Query
           .where(hidden: false)
           .joins("INNER JOIN data_explorer_query_groups
-                    ON data_explorer_query_groups.query_id = data_explorer_queries.id 
+                    ON data_explorer_query_groups.query_id = data_explorer_queries.id
                     AND data_explorer_query_groups.group_id = #{@group.id}")
         render_serialized(queries, DataExplorer::QuerySerializer, root: 'queries')
       end

app/models/data_explorer/query.rb

@@ -37,4 +37,3 @@ module DataExplorer
     end
   end
 end
-

app/models/data_explorer/query_group.rb

@@ -8,4 +8,3 @@ module DataExplorer
     belongs_to :group
   end
 end
-

app/serializers/data_explorer/query_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class DataExplorer::QuerySerializer < ActiveModel::Serializer
   attributes :id, :sql, :name, :description, :param_info, :created_at, :username, :group_ids, :last_run_at, :hidden, :user_id
 
@@ -13,4 +15,3 @@ class DataExplorer::QuerySerializer < ActiveModel::Serializer
     object.groups.map(&:id)
   end
 end
-

app/serializers/data_explorer/small_badge_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class DataExplorer::SmallBadgeSerializer < ApplicationSerializer
   attributes :id, :name, :badge_type, :description, :icon
 end

app/serializers/data_explorer/small_post_with_excerpt_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class DataExplorer::SmallPostWithExcerptSerializer < ApplicationSerializer
   attributes :id, :topic_id, :post_number, :excerpt, :username, :avatar_template
   def excerpt