Add MSC3916-compatible giphy media repo proxy

.gitlab-ci.yml

@@ -0,0 +1,10 @@
+build giphy proxy docker:
+  image: docker:stable
+  stage: build
+  before_script:
+  - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+  script:
+  - docker build -t $CI_REGISTRY_IMAGE/giphyproxy:latest giphyproxy
+  - docker push $CI_REGISTRY_IMAGE/giphyproxy:latest
+  only:
+  - master