JavaScript: Add configuration-file snippet to dbscheme.

javascript/ql/src/semmlecode.javascript.dbscheme

@@ -934,7 +934,8 @@ case @json_value.kind of
     | @cfg_node
     | @jsdoc | @jsdoc_type_expr | @jsdoc_tag
     | @yaml_locatable
-    | @xmllocatable;
+    | @xmllocatable
+    | @configLocatable;
 
 hasLocation (unique int locatable: @locatable ref,
     int location: @location ref);
@@ -1109,4 +1110,29 @@ xmllocations(
 
 isOptionalChaining(int id: @optionalchainable ref);
 
-/* Last updated 2018/10/23. */
+/*
+ * configuration files with key value pairs
+ */
+
+configs(
+  unique int id: @config
+);
+
+configNames(
+  unique int id: @configName,
+  int config: @config ref,
+  string name: string ref
+);
+
+configValues(
+  unique int id: @configValue,
+  int config: @config ref,
+  string value: string ref
+);
+
+configLocations(
+  int locatable: @configLocatable ref,
+  int location: @location_default ref
+);
+
+@configLocatable = @config | @configName | @configValue;