added ranking module to symbols in package level

Author: hideaki-t

sqlitefts/__init__.py

@@ -1,4 +1,4 @@
 from .tokenizer import Tokenizer, make_tokenizer_module, register_tokenizer
-from . import tokenizer
+from . import tokenizer, ranking
 
-__all__ = ["Tokenizer", "make_tokenizer_module", "register_tokenizer", "tokenizer"]
+__all__ = ["Tokenizer", "make_tokenizer_module", "register_tokenizer", "tokenizer", "ranking"]