Memory corruption caused by calling ctx.getPostParams("username")
Good work on this project I like its direction. I'm running the blog example and I get a memory corruption after successfully logging in. Offending code is in 21 of base.nim 

```nim
let username = ctx.getPostParams("username")
```

![Memory corruption](https://user-images.githubusercontent.com/853846/79689726-f0626500-8256-11ea-9203-05e1931a6385.png)