PWA support - Make it installable on any device and show offline page when user's internet is not connected

[akshitdandyan]

We can make frontendstudygroup web app a PWA due to following reasons:

• We can show offline page when user is not connected to internet.
• We can make website work in background even if user has not opened it, to serve purposes like sending notifications.
• Mainely, it will reduce overall loading time of website as it will store some sources in browser's cache memory.

[sunithapatel]

This is interesting. Currently it works as a single page app that shows pretty much static information, so it is not really making any more network calls after the first one to load the page.

I wonder if we need to have some functionality in the app that can be worked on offline first, before we implement this? Currently there isn't much that can be done if you're offline.

If you have more detail on what this would entail, that would be helpful. What would you envision doing to implement this?

[akshitdandyan]

@sunithapatel It will not only work in case of network calls, think of scenario where user's device is not connected to internet and he/she tries to visit the website, then we can show a beautiful and simple static html page informing user that you are not connected with help of PWA, rather then browser show default 'not connected page'. It can be a plus point and it does not require much codebase and efforts.

[sunithapatel]

Sure, go for it! I am not completely familiar with how it works, so will be curious to see. :)

[princiya]

fixed #38