Update README.md

Author: morrien

README.md

@@ -1,10 +1,22 @@
 # Push test coverage script runnable in bitbucket pipelines
 
 ## Setup
-- add `TEST_COVERAGE_USERNAME`, `TEST_COVERAGE_PASSWORD`, `TEST_COVERAGE_URL` to environment variables
+- add `TEST_COVERAGE_USERNAME`, `TEST_COVERAGE_PASSWORD`, `TEST_COVERAGE_URL` to environment variables (BB / local)
 - make sure to use this syntax -> **VARIABLE=VALUE** <- (not *VARIABLE='VALUE'*)
 
-## Implementation
-- `export $(cat .env | xargs) && npx GoodRequest/test-coverage-push-script || exit 1`
+## Local testing
+- **CAUTION: `export` may print environment variables to terminal on some systems**
+- invoke as `export $(cat .env | xargs) && npx GoodRequest/test-coverage-push-script`
 - exporting output from .env / xargs makes environment variables accessible to this script
-- `... || exit 1` explicitly kills the pipeline if npx script throws in any way
+
+## Implementation (example bitbucket-pipelines.yml step)
+```yml
+- step:
+  name: Test code
+  script:
+    - npm run db:init:test
+    - npm run test:coverage
+    - npx GoodRequest/test-coverage-push-script
+  services:
+    - mssql
+```