add generation csv service

app/services/generate_open_data_csv_service.rb

@@ -0,0 +1,19 @@
+class GenerateOpenDataCsvService
+  def self.save_csv_to_tmp(file_name, data)
+    f = Tempfile.create(["#{file_name}_#{date_last_month}", '.csv'], 'tmp')
+    f << generate_csv(file_name, data)
+    f.rewind
+    yield f if block_given?
+    f.close
+  end
+
+  def self.date_last_month
+    Date.today.prev_month.strftime("%B")
+  end
+
+  def self.generate_csv(file_name, data)
+    headers = ["mois", file_name]
+    data = [[date_last_month, data]]
+    SpreadsheetArchitect.to_csv(headers: headers, data: data)
+  end
+end