chore(gulp): create gulp task for application

create gulp to start the application, move the string.js file into public folder and watch for file changes

.env

@@ -0,0 +1 @@
+PORT=5000

.gitignore

@@ -1,2 +1,3 @@
 node_modules
-coverage
+coverage
+public/js/string.js

gulpfile.js

@@ -0,0 +1,27 @@
+require('dotenv').config();
+
+const gulp = require('gulp');
+const plugins = require('gulp-load-plugins')();
+
+const build = './public/';
+
+gulp.task('source', () => gulp.src('./src/string.js')
+  .pipe(gulp.dest('./public/js'))
+  .pipe(plugins.connect.reload()));
+
+gulp.task('serve', ['build', 'watch'], () => {
+  plugins.connect.server({
+    root: build,
+    port: process.env.PORT || 8080,
+    livereload: true,
+    fallback: `${build}index.html`
+  });
+});
+
+gulp.task('watch', () => {
+  gulp.watch('./src/string.js', ['source']);
+});
+
+gulp.task('build', ['source']);
+
+gulp.task('default', ['serve']);