implement sqlite database

src/lib.rs

@@ -244,6 +244,9 @@ pub extern crate electrum_client;
 #[cfg(feature = "key-value-db")]
 pub extern crate sled;
 
+#[cfg(feature = "sqlite")]
+pub extern crate rusqlite;
+
 #[allow(unused_imports)]
 #[macro_use]
 pub(crate) mod error;