node-sass command is incorrect.

[rupav]

Expected Behaviour

node-sass was added in #13.
node-sass is great because of its fast compilation over sass (refer Libsass vs sass )
with reference to https://github.com/sass/node-sass#command-line-interface, --style should be replaced with --output-style, and there should be no : in between input and output file path.

Actual Behaviour

currently running yarn run sass creates error. which can be solved with above suggestion.

Steps to Reproduce:

I will correct this in PR #30
Corrected locally:

[rupav]

Solved in #51