sass error

/* require */
var gulp = require('gulp'),
		browserSync = require('browser-sync'),
		reload = browserSync.reload,
		sass = require('gulp-ruby-sass'),
		plumber = require('gulp-plumber'),
		rename = require('gulp-rename'),
		uglify = require('gulp-uglify'),
		minifyCss = require('gulp-minify-css'),
		imagemin = require('gulp-imagemin'),
		pngquant = require('imagemin-pngquant'),
		autoprefixer = require('gulp-autoprefixer');


/* SASS tasks */
gulp.task('sass', function () {
  return sass('sass/')
  	.pipe(plumber())
    .on('error', sass.logError)
    .pipe(autoprefixer('last 3 versions'))
    .pipe(gulp.dest(''))
    .pipe(reload({stream:true}));
});

/* HTML tasks */
gulp.task('html', function() {
	gulp.src('./**/*.html')
	.pipe(reload({stream:true}));
});

/* JS tasks */
gulp.task('scripts', function() {
	gulp.src('./js/**/*.js')
	.pipe(reload({stream:true}));
});

/* browser-sync tasks - start the server */
gulp.task('browser-sync', function() {
	browserSync({
		server:{
			baseDir: ""
		}
	});
});

/* watch tasks */
gulp.task('watch', function() {
	gulp.watch('./sass/**/*.scss', ['sass']);
	gulp.watch('./**/*.html', ['html']);
	gulp.watch('./js/*.js', ['scripts']);
});

/* uglify js task */
gulp.task('uglify', function() {
	gulp.src('./js/**/*.js')
	.pipe(rename({suffix: '.min'}))
	.pipe(uglify())
	.pipe(gulp.dest('./js'));
});

/* minify css */
gulp.task('minify-css', function() {
	return gulp.src('./*.css')
	.pipe(rename({suffix: '.min'}))
	.pipe(minifyCss())
	.pipe(gulp.dest('./'));
});

/* compress images */
gulp.task('img-compress', function() {
	return gulp.src('./img/*')
	.pipe(imagemin({
      progressive: true,
      optimizationLevel: 4,
      svgoPlugins: [{removeViewBox: false}],
      use: [pngquant()]
  }))
  .pipe(gulp.dest('./img/img-min'));
});


/* default task - start server, autoprefix and compile sass, reload */
gulp.task('default', ['sass', 'scripts', 'html', 'browser-sync', 'watch']);