Set raw_data to an empty hash instead of nil when archiving

app/services/points/raw_data/archiver.rb

@@ -121,7 +121,7 @@ module Points
           Point.where(id: point_ids).update_all(
             raw_data_archived: true,
             raw_data_archive_id: archive_id,
-            raw_data: nil
+            raw_data: {}
           )
         end
       end

spec/services/points/raw_data/archiver_spec.rb

@@ -51,7 +51,7 @@ RSpec.describe Points::RawData::Archiver do
       it 'nullifies raw_data column' do
         archiver.call
         Point.where(user: user).find_each do |point|
-          expect(point.raw_data).to be_nil
+          expect(point.raw_data).to eq({})
         end
       end