Allow users to export cheat sheet as PDF

[kaushalyap]

First of all thanks for creating a such a useful project.

Currently website does not allow to export cheat sheets as PDF. Yes we could just right click on the page > print and export as PDF but the exported file is not properly formatted.

So please allow users to export file as PDF from the website with proper formatting.

Following libraries may become helpful when implementing this feature

• https://github.com/foliojs/pdfkit
• https://github.com/MrRio/jsPDF
• https://github.com/eKoopmans/html2pdf.js

[sematgt]

Or maybe we should implement not buggy print view.