Add gitlab ci

.gitlab-ci.yml

+image: "python:3-slim"
+
+cache:
+  paths:
+    - .cache/pip
+
+stages:
+  - pull
+  - build
+  - deploy
+
+build:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE != "schedule"'
+  stage: build
+  before_script:
+    - pip install -r requirements.txt
+  script:
+    - make html
+  variables:
+    PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
+  artifacts:     
+    expire_in: 1 month
+    paths:       
+      - _build/html
+
+deploy:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE != "schedule" && $CI_PROJECT_NAMESPACE == "bitcoin-dot-org" && $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'
+  stage: deploy
+  image: instrumentisto/rsync-ssh:latest
+  before_script:
+    # Run ssh-agent
+    - eval $(ssh-agent -s)
+    - mkdir -p ~/.ssh && chmod 700 ~/.ssh
+    - echo "${SSH_PRIVATE_KEY}" | base64 -d | ssh-add - > /dev/null
+    - echo "${SSH_HOST_KEY}" > ~/.ssh/known_hosts
+  script:
+    - rsync -azhv --delete _build/html/ "${SSH_USER_HOST_LOCATION}"
+
+repo_pull_sync:
+  stage: pull
+  image: danger89/repo_mirror_pull:latest
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+    - if: $REMOTE_URL
+    - if: $REMOTE_BRANCH
+    - if: $ACCESS_TOKEN
+  before_script:
+    - git config --global user.name "${GITLAB_USER_NAME}"
+    - git config --global user.email "${GITLAB_USER_EMAIL}"
+  script:
+    - git checkout $CI_DEFAULT_BRANCH
+    - git pull
+    - git remote remove upstream || true
+    - git remote add upstream $REMOTE_URL
+    - git fetch upstream
+    - git merge upstream/$REMOTE_BRANCH
+    - git push "https://${GITLAB_USER_LOGIN}:${ACCESS_TOKEN}@${CI_REPOSITORY_URL#*@}" "HEAD:${CI_DEFAULT_BRANCH}"