Adding import of topic custom fields

script/bulk_import/generic_bulk.rb

@@ -80,6 +80,7 @@ class BulkImport::Generic < BulkImport::Base
 
     import_topics
     import_posts
+    import_topic_custom_fields
     import_post_custom_fields
 
     import_polls
@@ -1073,6 +1074,32 @@ class BulkImport::Generic < BulkImport::Base
     post_custom_fields.close
   end
 
+  def import_topic_custom_fields
+    puts "", "Importing topic custom fields..."
+
+    topic_custom_fields = query(<<~SQL)
+      SELECT *
+      FROM topic_custom_fields
+      ORDER BY topic_id, name
+    SQL
+
+    field_names =
+      query("SELECT DISTINCT name FROM topic_custom_fields") { _1.map { |row| row["name"] } }
+    existing_topic_custom_fields =
+      TopicCustomField.where(name: field_names).pluck(:topic_id, :name).to_set
+
+    create_topic_custom_fields(topic_custom_fields) do |row|
+      topic_id = topic_id_from_imported_id(row["topic_id"])
+      next if topic_id.nil?
+
+      next if existing_topic_custom_fields.include?([topic_id, row["name"]])
+
+      { topic_id: topic_id, name: row["name"], value: row["value"] }
+    end
+
+    topic_custom_fields.close
+  end
+
   def import_polls
     unless defined?(::Poll)
       puts "", "Skipping polls, because the poll plugin is not installed."