Exams page more code

sql/exam_entry.sql

@@ -1,7 +1,7 @@
-create table exam_entry
+create table exam_entries
 (
     id      integer primary key,
-    exam_id integer not null references exam on delete cascade,
+    exam_id integer not null references exams on delete cascade,
     word_id integer not null references words on delete cascade,
     status integer default null
 );