link to new doc from index

doc/README.md

@@ -93,7 +93,7 @@ Manage files and branches from the UI (user interface):
   - [Checkout merge requests locally](user/project/merge_requests/index.md#checkout-merge-requests-locally)
   - [Cherry-pick](user/project/merge_requests/cherry_pick_changes.md)
 - [Milestones](user/project/milestones/index.md): Organize issues and merge requests into a cohesive group, optionally setting a due date.
-  - **(EES/EEP)** [Burndown Charts](user/project/milestones/index.md#burndown-charts): Watch your project's progress throughout a specific milestone.
+  - **(EES/EEP)** [Burndown Charts](user/project/milestones/burndown_charts.md): Watch your project's progress throughout a specific milestone.
 - [Related issues](user/project/issues/related_issues.md)
 - [Todos](workflow/todos.md): A chronological list of to-dos that are waiting for your input, all in a simple dashboard.