add sql patching facilities

This includes the patches to get from the initial version of the
database to its current state - for the purpose of documentation.

Beware, if you already have an existing database, running this code
will likely result in an error and/or lead to some minor data loss.
You need to follow these steps to fix your DB:
1. delete all *.sql files from unwind/sql/
2. remove the .disabled suffix from unwind/sql/00000001-fix-db.sql.disabled
3. start the application once, this will fix up the database
4. revert all changes to unwind/sql/ – or leave it, it doesn't matter.

unwind/sql/00000000-init-4.sql

@@ -0,0 +1,37 @@
+-- denormalize movie media_type
+
+CREATE TABLE _migrate_movies (
+    id TEXT PRIMARY KEY NOT NULL,
+    title TEXT NOT NULL,
+    original_title TEXT,
+    release_year INTEGER NOT NULL,
+    media_type TEXT NOT NULL,
+    imdb_id TEXT NOT NULL UNIQUE,
+    score INTEGER,
+    runtime INTEGER,
+    genres TEXT NOT NULL,
+    updated TEXT NOT NULL
+);;
+
+INSERT INTO _migrate_movies
+SELECT
+    id,
+    title,
+    original_title,
+    release_year,
+    (SELECT name FROM mediatypes WHERE id=media_type_id) AS media_type,
+    imdb_id,
+    score,
+    runtime,
+    genres,
+    updated
+FROM movies
+WHERE true;;
+
+DROP TABLE movies;;
+
+ALTER TABLE _migrate_movies
+RENAME TO movies;;
+
+DROP VIEW movies_view;;
+DROP TABLE mediatypes;;