Add mrt package issue on MAC

I need to add mrt package to meteor project using third party packages.In this i install npm and meteorite but adding packages to meteor project in this time gets the below error :

 mrt add router

Error :

✓ router
    tag: https://github.com/tmeasday/meteor-router.git#v0.6.1
ERROR: 128 Command failed: fatal: Not a git repository (or any of the parent directories): .git


STDOUT:  

STDERR: fatal: Not a git repository (or any of the parent directories): .git



/usr/local/lib/node_modules/meteorite/lib/sources/git.js:181
            self.checkoutType + ": " + (self.commit || self.head);
                                     ^
There was a problem checking out tag: v0.6.1

I am new to Meteor.So ididn't get any idea about this error.Please suggest me what to do ?