Update lefthook config.

lefthook.yml

@@ -1,35 +1,9 @@
-# EXAMPLE USAGE:
-#
-#   Refer for explanation to following link:
-#   https://github.com/evilmartians/lefthook/blob/master/docs/full_guide.md
-#
-# pre-push:
-#   commands:
-#     packages-audit:
-#       tags: frontend security
-#       run: yarn audit
-#     gems-audit:
-#       tags: backend security
-#       run: bundle audit
-#
-# pre-commit:
-#   parallel: true
-#   commands:
-#     eslint:
-#       glob: "*.{js,ts,jsx,tsx}"
-#       run: yarn eslint {staged_files}
-#     rubocop:
-#       tags: backend style
-#       glob: "*.rb"
-#       exclude: "application.rb|routes.rb"
-#       run: bundle exec rubocop --force-exclusion {all_files}
-#     govet:
-#       tags: backend style
-#       files: git ls-files -m
-#       glob: "*.go"
-#       run: go vet {files}
-#   scripts:
-#     "hello.js":
-#       runner: node
-#     "any.go":
-#       runner: go run
+pre-commit:
+  parallel: true
+  commands:
+    audit:
+      run: brakeman --no-pager
+    rubocop:
+      files: git diff --name-only --staged
+      glob: "*.rb"
+      run: rubocop --force-exclusion {files}