Add a new docker image with only prokka

Installation script should install only the pipeline, as barrnap is not necessary to run prokka

.gitlab-ci.yml

@@ -38,3 +38,13 @@ build-install-barrnap:
     - git checkout master -- pythoncode/requirements.txt
     - docker build --pull -t "$CI_REGISTRY_IMAGE:install-ubuntu-barrnapOnly" for_build/barrnap_only
     - docker push "$CI_REGISTRY_IMAGE:install-ubuntu-barrnapOnly"
+
+build-install-prokka:
+  only:
+    - docker
+  stage: build
+  script:
+    - apk update ; apk add git
+    - git checkout master -- pythoncode/requirements.txt
+    - docker build --pull -t "$CI_REGISTRY_IMAGE:install-ubuntu-prokkaOnly" for_build/prokka_only
+    - docker push "$CI_REGISTRY_IMAGE:install-ubuntu-prokkaOnly"

for_build/prokka_only/Dockerfile

+from ubuntu:16.04
+
+# Update apt-get packages
+RUN apt-get update &&\
+    apt-get -y upgrade
+
+# Install package needed
+RUN apt-get install -y \
+        wget \
+        python3-pip
+
+# Update pip
+RUN pip3 install --upgrade pip
+
+# Install prokka:
+WORKDIR /tmp
+RUN apt-get install -y\
+        libdatetime-perl \
+        libxml-simple-perl \
+        libdigest-md5-perl \
+        git \
+        default-jre \
+        bioperl
+RUN git clone https://github.com/tseemann/prokka.git
+RUN /tmp/prokka/bin/prokka --setupdb
+RUN ln -s /tmp/prokka/bin/prokka /usr/local/bin