Fix DOCKER_OPTS fro Travis and download required images

.travis.yml

@@ -19,7 +19,8 @@ before_install:
 #  - export DOCKER_HOST=tcp://192.168.23.75:2375
   - sudo service docker restart
   - sleep 5
-  - docker pull openhpi/docker_ruby
+  - docker pull openhpi/co_execenv_python
+  - docker pull openhpi/co_execenv_java
 
 before_script:
   - cp .rspec.travis .rspec

config/docker.yml.erb.travis

@@ -36,5 +36,5 @@ production:
 
 test:
   <<: *default
-  host: tcp://192.168.59.104:2376
+  host: tcp://127.0.0.1:2376
   workspace_root: <%= File.join('/', 'shared', Rails.env) %>