instruction: From the passage provided, extract the month and year when Cassandra was released on Google code
context: Avinash Lakshman, one of the authors of Amazon's Dynamo, and Prashant Malik initially developed Cassandra at Facebook to power the Facebook inbox search feature. Facebook released Cassandra as an open-source project on Google code in July 2008. In March 2009, it became an Apache Incubator project. On February 17, 2010, it graduated to a top-level project.
  
  Facebook developers named their database after the Trojan mythological prophet Cassandra, with classical allusions to a curse on an oracle.
response: Facebook released Cassandra as an open-source project on Google code in July 2008.