Added docker image test for CI

3 jobs for master in 1 minute and 37 seconds (queued for 41 seconds)
Status Job ID Name Coverage
  Build
passed #397
C
build:7-8.1

00:00:11

 
  Test
passed #398
C
test:7-8.1

00:00:20

 
  Docker
passed #399
docker
docker:7-8.1

00:01:05