Add Google Analytics

[matklad]

closes #20

[mkaput]

I'd like to emphasise my worries about this.

I agree that some analytics would be nice; though I'd prefer them to be publicly available; not only visible to the person who has set them up.

As an open source project, I believe limiting visibility of some data related to it is slightly inappropriate. I agree that stuff like IP addresses must not be public, but they can be easily anonymised.

Even personally, as a person who authored this website, I would just love to see such stats, but not with the cost of appropriating this privilege.

I think, different analytics provider is the way to go here. Open solutions like Piwik seems reasonable, but somebody has to set up them. I have no funds to do this unfortunately.

[matklad]

I also would prefer an open solution, but in the free and "as a service" form. I don't want to put an effort into maintaining our own analytics at this stage of the project :)

I am also Ok with using GA (and https://www.rust-lang.org/ does this anyway ;) ) Having this info will probably make this web site better, but I don't think it is critical.

Feel free to reopen if you change your opinion about GA or find a more open and out of the box solution.

[mkaput]

lgtm as for now, and replace this with open alternative when we find out how