Document git submodule embedding

README.md

@@ -8,6 +8,37 @@ It is intended to be embedded into other Go applications that collect audit data
 
 For embedding instructions, see [`docs/embedding.md`](/Users/mchusavitin/Documents/git/reanimator/chart/docs/embedding.md).
 
+### As Git Submodule
+
+To embed `chart` into another repository as a git submodule:
+
+```bash
+git submodule add https://git.mchus.pro/reanimator/chart.git internal/chart
+git submodule update --init --recursive
+```
+
+In the host application's `go.mod`, point the module path at the checked-out submodule:
+
+```go
+replace reanimator/chart => ./internal/chart
+```
+
+Example mount inside the host application:
+
+```go
+mux.Handle("/chart/", http.StripPrefix("/chart", viewer.NewHandler(viewer.HandlerOptions{
+    Title: "Hardware Snapshot",
+})))
+```
+
+To update the submodule later:
+
+```bash
+git submodule update --remote internal/chart
+git add internal/chart
+git commit -m "Update reanimator chart submodule"
+```
+
 Standalone local run:
 
 ```bash