diff --git a/Customization.md b/Customization.md
index ce8db50..52f5389 100644
--- a/Customization.md
+++ b/Customization.md
@@ -159,6 +159,16 @@ supports LSP snippets but you don't like them, set the option to `false`.
 
 Example: `{"client": {"snippetSupport": false}}`
 
+#### `compilationDatabaseDirectory`
+
+Default: `""`
+
+If not empty, look for `compile_commands.json` in it, otherwise the file is retrieved in the project root.
+
+Useful when using out-of-tree builds with the compilation database being generated in the build directory.
+
+Example: `{"compilationDatabaseDirectory": "out/release"}`
+
 #### `diagnostics.onOpen` / `diagnostics.onChange` / `diagnostics.onSave`
 
 Default: `onOpen`: `0` / `onChange`: `1000` / `onSave`: `0`