Merge branch 'ci' into 'master'

chore: add gitlab ci

deploy backend to lambda with zappa
deploy frontend to s3 with awscli

See merge request !5

+stages:
+  - deploy:backend
+  - deploy:frontend
+
+variables:
+  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache"
+
+cache:
+  paths:
+    - "$CI_PROJECT_DIR/.cache"
+
+deploy:backend:
+  image: python:3.6.5
+  stage: deploy:backend
+  cache:
+    paths:
+      - "$CI_PROJECT_DIR/khubox-api/venv"
+  script:
+    - cd $CI_PROJECT_DIR/khubox-api
+    - pip install --upgrade pip
+    - pip install awscli
+    - aws configure set aws_access_key_id $AWS_ACCESS_KEY_ID
+    - aws configure set aws_secret_access_key $AWS_SECRET_ACCESS_KEY
+    - aws configure set region $AWS_DEFAULT_REGION
+    - pip install virtualenv
+    - python -m virtualenv venv
+    - source venv/bin/activate
+    - pip install -r requirements.txt
+    - zappa update
+
+deploy:frontend:
+  image: nikolaik/python-nodejs:python3.6-nodejs12-alpine
+  stage: deploy:frontend
+  cache:
+    paths:
+      - "$CI_PROJECT_DIR/.yarn"
+      - "$CI_PROJECT_DIR/khubox-front/node_modules"
+  script:
+    - cd $CI_PROJECT_DIR/khubox-front
+    - yarn config set cache-folder $CI_PROJECT_DIR/.yarn
+    - yarn install
+    - CI=false yarn build
+    - pip install awscli
+    - aws configure set aws_access_key_id $AWS_ACCESS_KEY_ID
+    - aws configure set aws_secret_access_key $AWS_SECRET_ACCESS_KEY
+    - aws configure set region $AWS_DEFAULT_REGION
+    - aws s3 cp ./build/ s3://khubox-deploy/ --recursive --include "*" --acl public-read
+    - aws cloudfront create-invalidation --distribution-id E1RC3LPJHL5VUA --paths "/*"