Add .gitlab-ci.yml

.gitlab-ci.yml

+stages:
+  - build
+ 
+variables:
+  DOCKER_HOST: tcp://docker:2375
+  DOCKER_DRIVER: overlay2
+
+before_script:
+  - docker login -u "gitlab-ci-token" -p ${CI_JOB_TOKEN} ${CI_REGISTRY}
+
+build:
+  stage: build
+  image: docker:stable
+  services:
+    - docker:dind
+  script:
+    - docker build -t git.poka.website:4567/destream-public/destream-blockchain .
+    - docker push git.poka.website:4567/destream-public/destream-blockchain
+  environment:
+    name: ${CI_COMMIT_REF_NAME}
+  only:
+    - merge-3.0.0 
+  
\ No newline at end of file