add a tool to export the HDS stories into a sqlite database

contrib/hds/scheme.sql

@@ -0,0 +1,19 @@
+DROP TABLE authors;
+CREATE TABLE authors (
+    name TEXT PRIMARY KEY,
+    sex INTEGER,
+    description
+);
+CREATE INDEX author_idx ON authors(name, sex);
+
+DROP TABLE stories;
+CREATE TABLE stories (
+    id INTEGER PRIMARY KEY,
+    title TEXT,
+    date TEXT,
+    category TEXT,
+    author TEXT REFERENCES authors,
+    body TEXT
+);
+
+CREATE INDEX stories_idx ON stories(id, category);