ruby 2.6

Dockerfile

@@ -20,7 +20,7 @@ RUN apt-get update && \
 # Install system dependencies
 RUN apt-get update && \
   apt-get install -y curl software-properties-common && \
-  apt-get install -y build-essential libpq-dev ruby2.3 ruby2.3-dev nodejs libmysqlclient-dev exiv2 \
+  apt-get install -y build-essential libpq-dev ruby2.6 ruby2.6-dev nodejs libmysqlclient-dev exiv2 \
   libexiv2-dev imagemagick cmake git pkg-config python libxml2-dev libxslt1-dev \
   libcurl4-openssl-dev mysql-client zipcmp libxrender1 libgeoip-dev unzip zipcmp file vim jhead \
   netcat-openbsd yarn libmaxminddb0 geoipupdate && \