[docker] Add healtcheck config. (#5)

* Run tests with 8.6.x

* Improve update instructions (drupal-composer#366)

Author: jmolivas

.travis.yml

@@ -36,7 +36,7 @@ install:
 
 script:
   - if [[ $RELEASE = dev ]]; then composer --verbose remove --no-update drupal/console; fi;
-  - if [[ $RELEASE = dev ]]; then composer --verbose require --no-update drupal/core:8.5.x-dev webflo/drupal-core-require-dev:8.5.x-dev; fi;
+  - if [[ $RELEASE = dev ]]; then composer --verbose require --no-update drupal/core:8.6.x-dev webflo/drupal-core-require-dev:8.6.x-dev; fi;
   - if [[ $RELEASE = dev ]]; then composer --verbose update; fi;
   - cd $TRAVIS_BUILD_DIR/web
   - ./../vendor/bin/drush site-install --verbose --yes --db-url=sqlite://tmp/site.sqlite

README.md

@@ -61,7 +61,7 @@ new release of Drupal core.
 
 Follow the steps below to update your core files.
 
-1. Run `composer update drupal/core --with-dependencies` to update Drupal Core and its dependencies.
+1. Run `composer update drupal/core webflo/drupal-core-require-dev symfony/* --with-dependencies` to update Drupal Core and its dependencies.
 1. Run `git diff` to determine if any of the scaffolding files have changed. 
    Review the files for any changes and restore any customizations to 
   `.htaccess` or `robots.txt`.