add development and production targets; run phpunit in container

.drone.yml

@@ -29,13 +29,13 @@ steps:
     commands:
       - composer install --no-progress --no-interaction --no-dev --optimize-autoloader
 
-  - name: build image
+  - name: build production image
     image: docker
     volumes:
       - name: dockersock
         path: /var/run/docker.sock
     commands:
-      - docker build -t notecat:latest .
+      - docker build --target production -t notecat:latest .
 
   - name: deploy on testing
     image: docker/compose