add formatter to gitlab ci

.gitlab-ci.yml

@@ -2,6 +2,7 @@ image: $CI_REGISTRY/r3/docker/julia-custom
 
 stages:
   - test
+  - check
   - deploy-doc
 
 test:
@@ -13,6 +14,23 @@ test:
   after_script:
     - julia --project=test/coverage test/coverage/coverage-summary.jl
 
+format:
+  stage: check
+
+  script:
+    - julia -e 'using JuliaFormatter; format(".", verbose=true)'
+
+  after_script:
+    - julia -e '
+          out = Cmd(`git diff --name-only`) |> read |> String
+          if out == ""
+              exit(0)
+          else
+              @error "Some files have not been formatted !!!"
+              write(stdout, out)
+              exit(1)
+          end'
+
 pages:
   stage: deploy-doc
   script: