Add character set options when opening DB connection

lib/impure/db_sqlite.nim

@@ -183,13 +183,14 @@ proc close*(db: TDbConn) {.tags: [FDb].} =
   ## closes the database connection.
   if sqlite3.close(db) != SQLITE_OK: dbError(db)
     
-proc open*(connection, user, password, database: string): TDbConn {.
-  tags: [FDb].} =
+proc open*(connection, user, password, database: string, 
+           charset: string = "UTF-8"): TDbConn {.tags: [FDb].} =
   ## opens a database connection. Raises `EDb` if the connection could not
   ## be established. Only the ``connection`` parameter is used for ``sqlite``.
   var db: TDbConn
   if sqlite3.open(connection, db) == SQLITE_OK:
     result = db
+    exec(result, sql"PRAGMA encoding = ?", [charset])
   else:
     dbError(db)