update docs

Author: clovis

docs/configure_web_app.md

@@ -70,12 +70,14 @@ $card-header-color: rgb(173, 66, 66);  // Card and table headers
 $focus-on-dark-color: #fff;            // Focus indicator on dark backgrounds (e.g. navbar)
 ```
 
-Once you've edited the theme file, rebuild the web application by running the following command from the `app/` directory:
+Once you've edited the theme file, rebuild the web application by running:
 
 ```bash
 npm run build
 ```
 
+> **Important:** This command must be run from the database's own `app/` directory (e.g. `/path/to/your_database/app/`), not from the PhiloLogic source directory.
+
 ## <a name="aggregation"></a>Configuring the aggregation report
 The aggregation report (much like faceted browsing) sums up results from concordances by metadata fields. What it can also do is break-up results from any metadata field
 into smaller groups of results. For instance, you can get results grouped by author, and for each author, you can break up results by title, all within the same results page.