Bugfix/25 - use insertIfNotExist

[DeepDiver1975]

Description

Fixes #25

ToDo

• [x] add phpunit to Makefile
• [x] run make test-php in drone with mysql
• [x] run make test-php in drone with postsql
• [ ] run make test-php in drone with oracle
• [x] run make test-php in drone with sqlite

Checklist:

• [x] Latest changes are published according to instructions in README.md

[phil-davis]

I rebased so that CI runs on top of another recent testing app change. This is ready to merge when CI passes.