Add clang-8 image for sequential ci and coverage

.gitlab-ci.yml

@@ -27,3 +27,22 @@ test:gcc8-seq-coverage:
     - cd build
     - make run_unit_tests
     - make coverage
+
+build:clang8-seq-coverage:
+  image: localhost:5000/ubuntu_clang8
+  stage: build
+  script:
+    - mkdir -p build
+    - cd build
+    - CXX=clang++-8 CC=clang-8 cmake .. -DCMAKE_BUILD_TYPE=Coverage -DCLANG_FORMAT=/usr/bin/clang-format-8
+    - make pugs
+
+test:clang8-seq-coverage:
+  image: localhost:5000/ubuntu_clang8
+  stage: test
+  dependencies:
+    - build:clang8-seq-coverage
+  script:
+    - cd build
+    - make run_unit_tests
+    - make coverage