ersti: sg command

psGrammar/demos/demoErsti/commands.jsgf

@@ -34,4 +34,6 @@ public <command> = [<robot>] ( <introduce> | <save> | <wait> | <goTo> | <followM
 
 <count> = (count the people);
 
-<explain> = (what can you do) | (explain your skills);
\ No newline at end of file
+<explain> = (what can you do) | (explain your skills);
+
+<store_groceries> = (store the groceries)
\ No newline at end of file