add GitHub repo with slides

1 job for master in 60 minutes and 1 second (queued for 1 second)
Name Stage Failure
image_build Build The script exceeded the maximum execution time set for the job
 ---> Using cache
---> 20ceb528852a
Step 5/10 : COPY install.R /tmp/
---> Using cache
---> 0b0070222983
Step 6/10 : RUN R CMD BATCH /tmp/install.R /tmp/install.Rout
---> Running in 5d08b2e54a6e
Pulling docker image gitlab/gitlab-runner-helper:x86_64-05161b14 ...
ERROR: Job failed: execution took longer than 1h0m0s seconds