[REFACTOR] custom deployment to private server

- removed variables and unnecessary postgres service (relates to commit 6e6c5ec6)

.gitlab-ci.yml

-variables:
-  POSTGRES_DB: $DB_NAME
-  POSTGRES_USER: $DB_USER
-  POSTGRES_PASSWORD: $DB_PASSWORD
-  POSTGRES_HOST_AUTH_METHOD: $DB_HOST_AUTH_METHOD
-  AWS_ACCESS_KEY_ID: $AWS_ACCESS_KEY_ID
-  AWS_SECRET_ACCESS_KEY: $AWS_SECRET_ACCESS_KEY
-  AWS_STORAGE_BUCKET_NAME: $AWS_STORAGE_BUCKET_NAME
-
-services:
-  - postgres:12.2-alpine
-
 stages:
   - test
   - linter
   - sonarqube
-  - staging
-  - production
+  - deployment
 
 UnitTest:
   image: python:3.7
@@ -43,10 +30,11 @@ Pylint:
     - pip install -r requirements.txt
   when: on_success
   script:
-    - pylint --load-plugins pylint_django --rcfile=./.pylintrc informasi_fasilitas layanan_khusus new_rest_api oauth registrasi
+    - pylint --load-plugins pylint_django --rcfile=./.pylintrc \
+      informasi_fasilitas layanan_khusus new_rest_api oauth registrasi
 
 SonarScanner:
-  image: 
+  image:
     name: sonarsource/sonar-scanner-cli:latest
     entrypoint: [""]
   stage: sonarqube
@@ -57,30 +45,13 @@ SonarScanner:
       -Dsonar.branch.name=$CI_COMMIT_REF_NAME
       -Dsonar.projectKey=$SONARQUBE_PROJECT_KEY
 
-Staging:
-  image: ruby:2.4
-  stage: staging
-  only:
-    refs:
-      - staging
-  before_script:
-    - gem install dpl
-    - wget -qO- https://cli-assets.heroku.com/install-ubuntu.sh | sh
-  script:
-    - dpl --provider=heroku --app=$HEROKU_APPNAME_STAGING --api-key=$HEROKU_APIKEY
-    - export HEROKU_API_KEY=$HEROKU_APIKEY
-    - heroku run --app $HEROKU_APPNAME_STAGING migrate
-  environment:
-    name: staging
-    url: $HEROKU_APP_HOST_STAGING
-
-  
 Deployment:
   image: ruby:2.4
-  stage: production
+  stage: deployment
   only:
     refs:
-      - master
+      - staging
+      - development
   before_script:
     - apt-get update -qq
     - apt-get install -qq git
@@ -88,16 +59,10 @@ Deployment:
     - eval $(ssh-agent -s)
     - ssh-add <(echo "$SSH_PRIVATE_KEY" | base64 -d)
     - mkdir -p ~/.ssh
-    - '[[ -f /.dockerenv ]] && echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config'
+    - echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config
   script:
-    - >
-      ssh $TARGET_USER_AT_HOST 
-      "cd bisago-be &&
-      git checkout master &&
-      git pull origin master &&
-      bash stop.sh &&
-      bash start.sh &&
-      exit"
+    - result=$(ssh $TARGET "bash deployment/reload.sh $CI_COMMIT_REF_NAME")
+    - echo "$result"
+    - [ '$(echo "$result" | tail -n 1)' != "success" ] && exit 1
   environment:
-    name: production
-    url: $HEROKU_APP_HOST
\ No newline at end of file
+    name: deployment