Added Exceptions info

Author: stefanak-michal

README.md

@@ -7,6 +7,9 @@ extensions:
 - sockets https://www.php.net/manual/en/book.sockets.php
 - mbstring https://www.php.net/manual/en/book.mbstring.php
 
+## Exceptions
+Throwing exceptions is default behaviour. If you want, you can assign own callable error handler to ``\Bolt\Bolt::$errorHandler``. It's called on error and methods (init, run, pullAll, ...) will return false.
+
 ## Author note
 I really like Neo4j and I wanted to use it with PHP. But after I looked on official php library, I was really disappointed. Too much dependencies. I don't like if I need to install 10 things because of one. First I decided to use HTTP API for communication, but it wasn't fast enough. I went through bolt protocol documentation and I said to myself, why not to create own simpler library?