node.js - Error installing grunt-sass -

i'm trying install grunt-sass using npm, according said here, running following command

npm install --save-dev grunt-sass 

it happens i'm receiving error message:

unmet peer dependency grunt@>=0.4.0 

and again

npm warn grunt-contrib-sass@1.0.0 requires peer of grunt@>=0.4.0 none installed. npm warn grunt-sass@1.2.0 requires peer of grunt@>=0.4.0 none installed. 

but when run

grunt --version 

i following result

grunt-cli v1.2.0 grunt v0.4.5 

this says have grunt 0.4.5 , requires 0.4.0, should working fine.

any suggestions causing this?

it got resolved when intalled gem sass. had was

gem install sass 

and then

grunt build 

it seems there dependency here, says nothing in error message 1 find out. documentation problem, more bug.