Added YaML for gitlab pages deployment

.gitlab-ci.yml

+stages:
+  - deploy
+
+pages:
+  stage: deploy
+
+  script:
+    - make presentations
+    - mkdir .public
+    - cp ipnyb/*.html .public
+    - mv .public public
+
+  artifacts:
+    paths:
+      - .public
+  only:
+    - master
+    - web