Instructions for running integration tests

integration/README.md

@@ -42,6 +42,29 @@ The `images/` folders hosts some images for Ruby applications.
 
 Ruby base images include `Datadog::DemoEnv` and other helpers.
 
+### Running Integration Tests
+
+1. Pick an application to run the tests against:
+
+    ```
+    cd apps/rails-seven
+    ```
+
+2. Pick a Ruby version and build Docker images:
+
+    ```
+    ./script/build-images -v 3.3
+    ```
+
+Note: you need to build the images using this command whenever you make
+any changes in the source code.
+
+3. Run integration test script:
+
+    ```
+    ./script/ci -v 3.3
+    ```
+
 ### Debugging
 
 #### Profiling memory