$ docker build .
[+] Building 7.9s (10/10) FINISHED
 => [internal] load .dockerignore                                                                                                                                                                                      0.0s
 => => transferring context: 2B                                                                                                                                                                                        0.0s
 => [internal] load build definition from Dockerfile                                                                                                                                                                   0.0s
 => => transferring dockerfile: 503B                                                                                                                                                                                   0.0s
 => [internal] load metadata for docker.io/library/ruby:2.5                                                                                                                                                            0.3s
 => [1/5] FROM docker.io/library/ruby:2.5@sha256:ecc3e4f5da13d881a415c9692bb52d2b85b090f38f4ad99ae94f932b3598444b                                                                                                      0.0s
 => [internal] load build context                                                                                                                                                                                      0.0s
 => => transferring context: 14.19kB                                                                                                                                                                                   0.0s
 => CACHED [2/5] RUN mkdir -p /usr/src/app                                                                                                                                                                             0.0s
 => [3/5] COPY . /usr/src/app/                                                                                                                                                                                         0.0s
 => [4/5] RUN cd /usr/src/app && bundle install                                                                                                                                                                        7.0s
 => [5/5] WORKDIR /usr/src/app                                                                                                                                                                                         0.0s
 => exporting to image                                                                                                                                                                                                 0.4s
 => => exporting layers                                                                                                                                                                                                0.4s
 => => writing image sha256:2e8f4d0ad9c785b389a68083a69f4c63af09c16f584189c6107663824bf6b2c6                                                                                                                           0.0s

$ docker run -dt -e JENKINS_URL=https://cd.nasqueron.org -p 4567:4567 2e8f4d0ad9c785b389a68083a69f4c63af09c16f584189c6107663824bf6b2c6