GUIDE.md in rspreadsheet-0.4.9 vs GUIDE.md in rspreadsheet-0.5.0

@@ -2,10 +2,11 @@
 ### Opening the file
 
 You can open ODS file (OpenDocument Spreadsheet) like this
 ````ruby
 workbook = Rspreadsheet.open('./test.ods')
+workbook = Rspreadsheet.open('./test.fods') # gem supports flast OpenDocument format
 ````
 and access its first sheet like this
 ````ruby
 sheet = workbook.worksheet(1)
 ````
@@ -35,12 +36,27 @@
 
 ### Saving 
 The file needs to be saved after doing changes. 
 ````ruby
 workbook.save
-workbook.save('new_filename.ods')   # changes filename and saves
-workbook.save(any_io_object)        # file can be saved to any IO like object as well
+workbook.save('new_filename.ods')    # changes filename and saves
+workbook.save(any_io_object)         # file can be saved to any IO like object as well
+workbook.to_io                       # coverts it to IO object which can be used to 
+anotherIO.write(workbook.to_io.read) # send file over internet without saving it first
 ````
+
+### Creating fresh new file
+You may name the spreadsheet on creation or at first save.
+
+````ruby
+workbook = Rspreadsheet.new
+workbook.save('./filename.ods')      # filename nust be provided at least on first save
+workbook2 = Rspreadsheet.new('./filename2.fods', format: :flat)
+workbook2.save                       
+```
+
+If you want to use the fods flat format, you must create it as such.
+
 ### Date and Time
 OpenDocument and ruby have different models of date, time and datetime. Ruby containg three different objects. Time and DateTime cover all cases, Date covers dates only. OpenDocument distinguishes two groups - time of a day (time) and everything else (date). To simplify things a little we return cell values containg time of day as Time object and cell values containg datetime of date as DateTime. I am aware that this is very arbitrary choice, but it is very practical. This way and to some extend the types of values from OpenDocument are preserved when read from files, beeing acted upon and written back to spreadshhet.
 
 ### Merged cells 
 Even when a cell spans more rows and collumns, you must access by coordinates of its topleft corner. In fact, the "hidden" cells under are still there and their content is usually preserved.