Added (experimental) schema for PostgreSQL.

doc/schema.pgsql

@@ -0,0 +1,49 @@
+create table sessions (
+    id serial primary key,
+    start_date int,
+    end_date int,
+    prefix varchar
+);
+
+create table filesets (
+    id serial primary key,
+    host varchar,
+    dir varchar,
+    options varchar
+);
+
+create table files (
+    id serial primary key,
+    path varchar,
+    fileset int references filesets(id)
+);
+
+create table versions2 (
+    id serial primary key,
+    file_type char(1),
+    file_size int8,
+    file_mtime int,
+    file_owner varchar,
+    file_group varchar,
+    file_acl varchar,
+    file_unix_bits bit(3),
+    file_rdev int,
+    checksum varchar,
+    file_linktarget varchar
+);
+create index versions2_file_mtime_idx on versions2(file_mtime);
+create index versions2_checksum_idx on versions2(checksum);
+
+create table instances (
+    id serial primary key,
+    file int references files(id),
+    file_id varchar,
+    date int,
+    online boolean,
+    session int references sessions(id),
+    version int references versions2(id)
+);
+create index instances_file_idx on instances(file);
+create index instances_session_idx on instances(session);
+create index instances_version_idx on instances(version);
+