update: add .DS_Store to .gitignore for macOS system files (#29)

Author: AdalyatNazirov

.gitignore

@@ -189,7 +189,7 @@ publish/
 # Publish Web Output
 *.[Pp]ublish.xml
 *.azurePubxml
-# TODO: Comment the next line if you want to checkin your web deploy settings 
+# TODO: Comment the next line if you want to checkin your web deploy settings
 # but database connection strings (with potential passwords) will be unencrypted
 *.pubxml
 *.publishproj
@@ -227,6 +227,9 @@ ClientBin/
 node_modules/
 bower_components/
 
+# macOS system files
+.DS_Store
+
 # RIA/Silverlight projects
 Generated_Code/