Require code in season.

models.py

@@ -103,9 +103,11 @@ class Season:
             try:
                 end = datetime.date.fromisoformat(end)
             except Exception:
-                raise INVALID_STR.format('end')
+                raise AttributeError(INVALID_STR.format('end'))
 
         code = form.get('code', None)
+        if not code:
+            raise AttributeError(INVALID_STR.format('code'))
 
         self = cls(id, game, description, start, end, code)
         return self

schema.sql

@@ -7,7 +7,7 @@ create table if not exists season
 	description text,
 	start text,
 	end text,
-	code text
+	code text not null
 );
 
 create unique index if not exists season_id_uindex

templates/editseason.html

@@ -20,7 +20,8 @@
            type="text"
            class="form-control"
            id="code"
-           value="{{ model['code'] }}">
+           value="{{ model['code'] }}"
+           required>
   </div>
   <div class="form-group">
     <label for="game">Game Name</label>