Add link to repository-activity-score.md

Author: spier

patterns/1-initial/innersource-before-open-source.md

@@ -40,7 +40,7 @@ Before making a project open source, require it to go through an InnerSource pha
 1. The project is made available internally for contributions from other teams e.g. via an [InnerSource Portal](../2-structured/innersource-portal.md).
 2. Clear [documentation](../2-structured/base-documentation.md) (including contribution guidelines), and [governance structures](../2-structured/governance-levels.md) are established.
 3. Maintainers gain experience managing contributions, reviewing pull requests, and addressing issues.  
-4. Internal adoption and success metrics are measured to determine if the project is ready for external release.  
+4. Internal adoption and success metrics are measured to determine if the project is ready for external release. Some possible metrics are detailed in the [Repository Activity Score](../2-structured/repository-activity-score.md).
 5. Feedback loops are created to refine processes before engaging a broader open source audience.  
 
 ## Resulting Context