Login to private dockerr repo within script, move image into main script.

This is because we'll eventually be doing other builds as well.

.gitlab-ci.yml

@@ -1,6 +1,7 @@
-image: docker
 
 build:
+  image: vato.ddns.net:8083/docker
   stage: build
   script:
+    - ${DOCKER_PASSWORD} | docker login vato.ddns.net:8083 --username ${DOCKER_USERNAME} --password-stdin
     - docker build -f pycar/Dockerfile --build-arg PYPI_USERNAME=${PYPI_USERNAME} --build-arg PYPI_PASSWORD=${PYPI_PASSWORD} pycar