Update README file
|Target version:||Release 2.5.2|
|Google Code Legacy ID:||Tested version:|
Our README file in the AtoM repository is unstyled, points to the wrong place to find installation documentation, says very little about the project, and does not mention all the other related sites and resources we maintain.
This ticket is to update the CONTRIBUTING file in the AtoM repository with something more up-to-date, that addresses the above deficiencies.