Move everything to backend

backend/ddl.sql

@@ -0,0 +1,27 @@
+create table guild (
+	id integer primary key,
+	name text
+);
+create unique index idx_guild_name on guild(name);
+
+create table player (
+	id integer primary key,
+	name text,
+	guild integer references guild(id)
+);
+create unique index idx_player_name on player(name);
+
+create table association (
+	id integer primary key,
+	lhs integer references player(id),
+	rhs integer references player(id),
+	note text
+);
+
+create table note (
+	id integer primary key,
+	content text,
+	timestamp string,
+	player integer references player(id)
+);
+create unique index idx_note_content on note(timestamp, player);