And the same may be said about the products we make today 40 years from now. Survivorship bias is the logical error of concentrating on the things that made it past some selection process and overlooking those that did not.
Well, technically a file system is a specialized typed of database. NTFS has some support for removing duplicate files and replacing them with links. Windows server 2008 calls this feature "Single Instance Storage".
Wait, that didn't work. I got all kinds of errors and warnings. I must have the wrong version of something. You win, point taken.
There should be an easier way. I should be able to just run "apt-get install rails-easy" and have a system that is completely configured for development.
Pigments can sometimes be stubborn things. But I find that folks tend agree that darker greens are 'greener' than lighter greens. So for best results I'd use a dark green with a glossy finish. It should produce the greener hue that you are looking for.
Well, provided that this doesn't need to be highly secured. You could base invite keys on some property of the verification code. For example, you could design a system where a code is valid if the sum of the first five digits is equal to the product of the next three digits.
A system like that is easy to code and requires no database. The downside is that your would be relying on security by obscurity. For something like an invite system that may perfectly acceptable.