Gulp plugin gulp-ruby-sass(https://github.com/sindresorhus/gulp-ruby-sass) giving not compiling, the error message in terminal coming like this
Error: must provide pattern
Here is the gulpfile.js details
var gulp = require('gulp'),
  uglify = require('gulp-uglify'),
    sass = require('gulp-ruby-sass');
    gulp.task('styles', function (argument) {
        gulp.src('sass/app.scss')
            .pipe(sass())
            .pipe(gulp.dest('css/'));
    });
 
     
     
    