Add API to nullify log_data column

This commit add class method .reset_log_data for nullify
association and instance method #reset_log_data for nullify
single record.

lib/logidze/model.rb

@@ -53,6 +53,11 @@ def has_logidze?
         true
       end
       # rubocop: enable Naming/PredicateName
+
+      # Nullify log_data column for a association
+      def reset_log_data
+        without_logging { update_all(log_data: nil) }
+      end
     end
 
     # Use this to convert Ruby time to milliseconds
@@ -204,6 +209,11 @@ def reload_log_data
       self.log_data = self.class.where(self.class.primary_key => id).pluck(:log_data).first
     end
 
+    # Nullify log_data column for a single record
+    def reset_log_data
+      self.class.without_logging { update_column(:log_data, nil) }
+    end
+
     protected
 
     def apply_diff(version, diff)

spec/logidze/model_spec.rb

@@ -578,4 +578,30 @@
       it { is_expected.to be_zero }
     end
   end
+
+  describe '.reset_log_data' do
+    let!(:user2) { user.dup.tap(&:save!) }
+    let!(:user3) { user.dup.tap(&:save!) }
+
+    before { User.limit(2).reset_log_data }
+
+    it 'nullify log_data column for a association' do
+      expect(user.reload.log_size).to be_zero
+      expect(user2.reload.log_size).to be_zero
+    end
+
+    it 'not affect other model records' do
+      expect(user3.reload.log_size).to eq 5
+    end
+  end
+
+  describe '#reset_log_data' do
+    subject { user.log_size }
+
+    before { user.reset_log_data }
+
+    it 'nullify log_data colulmn for a single record' do
+      is_expected.to be_zero
+    end
+  end
 end