Add a task runner

[vitebo]

I tried to do it the simplest way so as not to have to change much in the repository, so I chose to use:

• gulp.
• npm version: 6.12.0
• node version: 10.16.3 LTS

just use npm run compile to compile the file.

OBS

One point I found important is that without adding autoprefixer, the minified file gets8.8kb, and when I add the file goes to 20kb. I did not know that these autoprefixer could make all this difference.

[vaibhav111tandon]

thank you for the changes @vitebo