rename tables

sql/words.sql

@@ -7,7 +7,7 @@ create table words
     tags     TEXT              not null,
     more     TEXT,
     group_id integer default 1 not null
-        constraint words_word_group_id_fk
-            references word_group
+        constraint words_word_groups_id_fk
+            references word_groups
             on update cascade on delete cascade
 );