CI: Generate documentation PDF

Change-Id: Ibcb602e2ef8738ca25938fae4306974b6a4d828f
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index be07f41..9723f90 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,5 +1,5 @@
 # use the tidyverse rocker image, as it contains devtools preinstalled
-image: rocker/tidyverse
+image: rocker/verse
 
 # define stages of runner. at the moment,
 # just test and build (no deploy).
@@ -9,8 +9,14 @@
 build-and-check:
   stage: build
   before_script:
-    - apt-get update && apt-get install -y build-essential libglpk40 libxt6
+    - apt-cache search libertinus
+    - apt-get update && apt-get install -y build-essential libglpk40 libxt6  fonts-linuxlibertine
+    - tlmgr install amsmath auxhook etoolbox fontspec gettitlestring hycolor hyperref infwarerr intcalc iftex kvdefinekeys kvoptions kvsetkeys letltxmacro libertinus libertinus-otf libertinus-fonts ltxcmds lualatex-math luatexbase pdftexcmds pdfescape pdflscape pdftexcmds refcount rerunfilecheck selnolig setspace stringenc tabu threeparttable threeparttablex trimspaces ulem unicode-math
   script:
     # install & check
     - R -e 'devtools::install()'
     - R CMD build . && R CMD check --no-manual $(ls -t . | head -n1)
+    - PDFLATEX=lualatex RD2PDF_INPUTENC='inputenc}\usepackage{fontspec}\usepackage{libertinus' R CMD Rd2pdf -o rderekovecs.pdf --no-description .
+  artifacts:
+    paths:
+      - rderekovecs.pdf