It's a simple application that allows you to commit to some data without showing it, and then revealing it afterwars along with a proof that the revealed data is the same as the one referenced by the commitment.

You need to install the meteor framework. You can install meteor in Linux/Mac OS X with:

$ curl https://install.meteor.com/ | sh

Then in the blindpromise subdirectory execute the following command:

$ meteor

More information about meteor apps deployment in https://meteor.com/learn