db: Add table for transactions we are interested in

Currently these are either transactions we sent ourselves or transactions that
we are watching because they are part of a channel.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

wallet/db.c

@@ -290,6 +290,16 @@ char *dbmigrations[] = {
     "     , msatoshi_to_us_max = msatoshi_local"
     "     ;",
     /* -- Min and max msatoshi_to_us ends -- */
+    /* Transactions we are interested in. Either we sent them ourselves or we
+     * are watching them. We don't cascade block height deletes so we don't
+     * forget any of them by accident.*/
+    "CREATE TABLE transactions ("
+    "  id BLOB"
+    ", blockheight INTEGER REFERENCES blocks(height) ON DELETE SET NULL"
+    ", txindex INTEGER"
+    ", rawtx BLOB"
+    ", PRIMARY KEY (id)"
+    ");",
     NULL,
 };