Update Maintaining.md

Author: Andrenzo17

Maintaining.md

@@ -5,6 +5,7 @@
 - Make your changes
 - Update `version` value on `version.rb` file
 - To install the package from local codes, you should build a gem `gem build veritrans.gemspec` after that `gem install veritrans-x.y.z.gem` (replace `x.y.z` with the version number e.g. `gem install veritrans-2.4.0.gem`)
+  - Note: In case you want to test another new code changes, you will need to re-build & re-install, so that your latest code will be used by the locally installed gem
 - To run all test `cd /lib/test` and after that `ruby -Itest all.rb`
 - To run specific test `ruby snap_test.rb`
 - If you are using Rubymine, you can right click folder test and choose `run all tests in test`