Add gitlab-ci file

.gitlab-ci.yml

+variables:
+
+stages:
+  - build
+
+before_script:
+  - apk update && apk add groff less && apk add python3
+  - pip3 install awscli
+  - (aws ecr get-login --no-include-email --region us-east-1) > login.sh
+  - sh login.sh
+
+after_script:
+  - docker logout "$AWS_ACCOUNT_ID".dkr.ecr.us-east-1.amazonaws.com
+
+image: docker:latest
+
+build-master:
+  stage: build
+  tags:
+    - docker
+  script:
+    - docker build -t enterprise-integrations/iics_secure_agent .
+    - docker tag enterprise-integrations/iics_secure_agent:latest "$AWS_ACCOUNT_ID".dkr.ecr.us-east-1.amazonaws.com/enterprise-integrations/iics_secure_agent:latest
+    - docker push "$AWS_ACCOUNT_ID".dkr.ecr.us-east-1.amazonaws.com/enterprise-integrations/iics_secure_agent:latest
+  only:
+    refs:
+      - master
+    changes:
+      - Dockerfile