docs: add GitLab CI / Code Climate example

Signed-off-by: gardar <gardar@users.noreply.github.com>

docs/integration.rst

@@ -65,3 +65,44 @@ You can configure yamllint to run on ``arc lint``. Here is an example
       }
     }
   }
+
+Intergration with GitLab
+------------------------
+
+You can use the following gitlab-ci stage to do run yamllint and get the results as a
+`Code quality (Code Climate) <https://docs.gitlab.com/ee/ci/testing/code_quality.html>` report.
+
+.. code:: yaml
+
+   ---
+   lint:
+     stage: lint
+     script:
+       - pip install yamllint
+       - mkdir reports
+       - >
+         yamllint -f parsable . | tee >(awk '
+         BEGIN {FS = ":"; ORS="\n"; first=1}
+         {
+             gsub(/^[ \t]+|[ \t]+$|"/, "", $4);
+             match($4, /^\[(warning|error)\](.*)\((.*)\)$/, a);
+             sev = (a[1] == "error" ? "major" : "minor");
+             if (first) {
+                 first=0;
+                 printf("[");
+             } else {
+                 printf(",");
+             }
+             printf("{\"location\":{\"path\":\"%s\",\"lines\":{\"begin\":%s,\"end\":%s}}," \
+                    "\"severity\":\"%s\",\"check_name\":\"%s\",\"categories\":[\"Style\"]," \
+                    "\"type\":\"issue\",\"description\":\"%s\"}",
+                    $1, $2, $3, sev, a[3], a[2]);
+         }
+         END { if (!first) printf("]\n"); }' > reports/codequality.json)
+     artifacts:
+       when: always
+       paths:
+         - reports
+       expire_in: 1 week
+       reports:
+         codequality: reports/codequality.json