Added example.

OnlineEditorsExample/OnlineEditorsExampleRuby/app/models/file_utility.rb

@@ -0,0 +1,31 @@
+class FileUtility
+
+  @@exts_document = %w(.docx .doc .odt .rtf .txt .html .htm .mht .pdf .djvu .fb2 .epub .xps)
+
+  @@exts_spreadsheet = %w(.xls .xlsx .ods .csv)
+
+  @@exts_presentation = %w(.ppt .pptx .odp)
+
+  class << self
+
+    def get_file_type(file_name)
+        ext = File.extname(file_name)
+
+        if @@exts_document.include? ext
+          return 'text'
+        end
+
+        if @@exts_spreadsheet.include? ext
+          return 'spreadsheet'
+        end
+
+        if @@exts_presentation.include? ext
+          return 'presentation'
+        end
+
+        'text'
+    end
+
+  end
+
+end