feat: Add .gitlab-ci.yml pipeline (#5)

Author: brendanator

.gitlab-ci.yml

@@ -0,0 +1,35 @@
+# Perform a code review on a merge request using the Sourcery review
+
+# GitLab setup instructions:
+# 1. Add the `sourcery_review` pipeline below into your project's `.gitlab-ci.yml`
+# 2. Create a Project/Group Access Token for posting reviews to merge requests - `SOURCERY_AI_BOT`
+#     - Go to Settings > Access Tokens
+#     - Create a new Access Token with name `SOURCERY_AI_BOT` and scope `api`
+#     - Click on "Create access token"
+# 3. Store your Sourcery token as a Project/Group CI/CD variable - `SOURCERY_TOKEN`
+#     - First get your Sourcery token
+#     - Go to Settings > CI/CD
+#     - Expand the Variables section.
+#     - Add a new variable:
+#         - Key: `SOURCERY_TOKEN`.
+#         - Value: <Your Sourcery token>
+#         - Flags:
+#             - ❌ Protect variable
+#             - ✅ Mask variable
+#             - ❌ Expand variable reference
+#     - Click on "Add variable"
+
+sourcery_review:
+  stage: test
+  image: python:slim
+  script:
+      - pip install --pre sourcery-nightly
+      - sourcery login --token $SOURCERY_TOKEN 
+      - |
+        sourcery assistant review gitlab-merge-request \
+            --gitlab-token $SOURCERY_AI_BOT \
+            --project $CI_PROJECT_PATH \
+            --merge-request $CI_MERGE_REQUEST_IID \
+            --commit $CI_COMMIT_SHA
+  rules:
+    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'