v1.1: Add weekly introductions

- Create a new migration adding a Weeks table, allowing for new weekly introductions
     and paving the way for multiple week handling.
 - Add route to update the weekly introduction
 - Move the week rendering to a specific week file
 - Update the templates to use the week number from the week data
 - Update templates to render and edit weekly introductions

db/03_create-week-table.sql

@@ -0,0 +1,10 @@
+CREATE TABLE IF NOT EXISTS Weeks (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    number INTEGER NOT NULL CHECK (number > 0),
+    is_last_week INTEGER NOT NULL,
+    rendered_text VARCHAR NOT NULL,
+    raw_text VARCHAR NOT NULL
+);
+
+-- This is to upgrade from version 1.0 to 1.1 with an existing database
+INSERT INTO Weeks (number, is_last_week, rendered_text, raw_text) VALUES (1, 1, "", "");