replaced the online JS minifier with a local program

dockerfiles/Dockerfile.nginx

@@ -7,15 +7,15 @@ FROM ubuntu
 LABEL maintainer="Alexander König <Alexander.Koenig@eurac.edu>"
 
 # install cpanm and dependencies
-RUN apt-get update &&\
-        apt-get -y upgrade &&\
-        apt-get -y install make gcc wget cpanminus
+RUN apt-get update \
+&&  apt-get -y install make gcc wget cpanminus
 
 RUN cpanm File::Spec::Functions
 RUN cpanm Term::ReadLine
 
 # install jdk, ant, psql, mvn, make, libxml, xsltproc, zip, wget
-RUN apt-get -y install openjdk-8-jdk ant maven libxml2-utils xsltproc unzip curl
+RUN apt-get update \
+&& apt-get -y install ant curl libxml2-utils maven openjdk-8-jdk unzip xsltproc yui-compressor
 
 # install convenience apps for debug purposes (vim and jsbeautifier)
 RUN apt-get -y install vim less python-pip
@@ -87,7 +87,8 @@ COPY commul-customization/shib_clear_headers /opt/nginx/conf/
 COPY commul-customization/aai.js /opt/repository/sources/lindat-aai-discovery/
 WORKDIR /opt/repository/sources/lindat-aai-discovery/
 RUN touch /opt/repository/sources/lindat-aai-discovery/aai.js
-RUN make aai.min.js
+# RUN make aai.min.js # this does not always work, because the website is often down
+RUN yui-compressor -o aai.min.js aai.js
 
 # copy certificate for clarin-dev
 # COPY commul-customization/certs/clarin-dev.key /etc/ssl/private/