switch to docker, add docker-compose

Author: vyuldashev

.travis.yml

@@ -5,22 +5,13 @@ php:
   - 7.2
   - 7.3
 
-env:
-  - DOCKER_COMPOSE_VERSION=1.23.2
-
 services:
   - docker
 
 cache:
   directories:
     - $HOME/.composer/cache
 
-before_install:
-  - sudo rm /usr/local/bin/docker-compose
-  - curl -L https://github.com/docker/compose/releases/download/${DOCKER_COMPOSE_VERSION}/docker-compose-`uname -s`-`uname -m` > docker-compose
-  - chmod +x docker-compose
-  - sudo mv docker-compose /usr/local/bin
-
 before_script:
   - travis_retry composer self-update
   - travis_retry composer update --no-progress --no-interaction --prefer-dist