Start a design document for Ocarina 6

Up until now I've just been coding whatever I feel like without thinking
about it too much.  This time I'm actually going to come up with an
ocarina design and then implement it according to the document.  The doc
can then act as a reference for how and why things are done for future
work.

Signed-off-by: Bryan Schumaker <bjschuma@gmail.com>

design.txt

@@ -0,0 +1,88 @@
+===============================================================================
+=                                                                             =
+=                                 Ocarina 6.0                                 =
+=                                                                             =
+===============================================================================
+
+My main goal for Ocarina 6.x is to stop writing my own solutions to problems
+that have already been solved.  For example, this means using SQL to store
+a library rather than developing my own file format.  This should help with
+future maintenance because I'll have less code to navigate.
+
+SQLite:
+	I plan on using SQLite for data storage as much as possible.  I had
+	been using my own custom file formats for storing preferences or
+	libraries, but this is turning into a hassle as I have more code that
+	needs to be maintained.  Try to use an SQLite prepared statement
+	whenever possible.
+
+		#include <sqlite3.h>
+
+		$ pkg-config --cflags --libs sqlite3
+
+Files:
+	$HOME/.ocarina{-debug}/ocarina.db
+
+Database: (ocarina.db)
+	Paths -
+		create table if not exists paths(
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			filepath TEXT UNIQUE, /* root path of library */
+			enabled INTEGER, /* 0 = false, 1 = true */
+		);
+
+	Artist -
+		create table if not exists artists(
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			name TEXT UNIQUE
+		);
+
+	Album -
+		create table if not exists albums(
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			name TEXT UNIQUE,
+			year SHORT INTEGER,
+		);
+
+	Tracks -
+		create table if not exists tracks(
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			FOREIGN KEY(path_id) REFERENCES paths(id),
+			FOREIGN KEY(artist_id) REFERENCES artists(id),
+			FOREIGN KEY(album_id) REFERENCES albums(id),
+			filepath TEXT UNIQUE, /* full path - libary root */
+			title TEXT,
+			comment TEXT,
+			genre TEXT,
+			lenstr TEXT,
+			track UNSIGNED INT,
+			count UNSIGNED INT DEFAULT 0,
+			last_day UNSIGNED INT DEFAULT 0,
+			last_month UNSIGNED INT DEFAULT 0,
+			last_year UNSIGNED INT DEFAULT 0,
+			length INT,
+			bitrate INT,
+			sample INT,
+			channels INT,
+			banned INT, /* 0 = false, 1 = true */
+		);
+
+	Playlist -
+		create table if not exists playlists(
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			flags UNSIGNED INTEGER
+		)
+
+	Playlist #N -
+		create table if not exists playlist{0-9}(
+			FOREIGN KEY(track) REFERENCES tracks(id),
+		);
+
+	User settings - 
+		create table if not exists config(
+			name PRIMARY KEY,
+			value INT,
+		);
+
+Archlinux packages:
+	extra/sqlite