adding ci and gitignore

.gitignore

+.DS_Store
+Thumbs.db
+db.json
+*.log
+node_modules/
+public/
+.deploy*/
\ No newline at end of file

.gitlab-ci.yml

+image: node:8.11.2
+
+pages:
+  cache:
+    paths:
+    - node_modules/
+
+  script:
+  - npm install hexo-cli -g
+  - npm install
+  - hexo deploy
+  artifacts:
+    paths:
+    - public
+  only:
+  - master