add first time social housing to bulk upload

app/services/bulk_upload/lettings/row_parser.rb

@@ -545,7 +545,7 @@ private
     attributes["hhmemb"] = hhmemb
 
     attributes["unitletas"] = field_105
-    attributes["rsnvac"] = field_106
+    attributes["rsnvac"] = rsnvac
     attributes["sheltered"] = field_117
 
     attributes["illness_type_1"] = field_119
@@ -571,9 +571,22 @@ private
 
     attributes["voiddate"] = voiddate
 
+    attributes["first_time_property_let_as_social_housing"] = first_time_property_let_as_social_housing
+
     attributes
   end
 
+  def first_time_property_let_as_social_housing
+    case rsnvac
+    when 15, 16, 17
+      1
+    end
+  end
+
+  def rsnvac
+    field_106
+  end
+
   def voiddate
     Date.new(field_91 + 2000, field_90, field_89) if field_91.present? && field_90.present? && field_89.present?
   end

spec/services/bulk_upload/lettings/row_parser_spec.rb

@@ -723,5 +723,15 @@ RSpec.describe BulkUpload::Lettings::RowParser do
         end
       end
     end
+
+    describe "#first_time_property_let_as_social_housing" do
+      context "when field_106 is 15, 16, or 17" do
+        let(:attributes) { { bulk_upload:, field_106: %w[15 16 17].sample } }
+
+        it "sets to 1" do
+          expect(parser.log.first_time_property_let_as_social_housing).to eq(1)
+        end
+      end
+    end
   end
 end