Add guide for system dependency for bootstrap

[Piping]

Hi,

I am trying out the example inside a relative new VM (ubuntu16.04).

The cargo test report a linker error at the end.

  = note: /usr/bin/x86_64-linux-gnu-ld: cannot find -lsqlite3
          /usr/bin/x86_64-linux-gnu-ld: cannot find -lpq
          /usr/bin/x86_64-linux-gnu-ld: cannot find -lmysqlclient
          collect2: error: ld returned 1 exit status

Is it possible to update the README to include some steps for a brand new linux VM setup?

[ddimaria]

Hi! Feel free to submit a PR for a more detailed README. I have a link to Diesel for error cases (http://diesel.rs/guides/getting-started/), but having that info in the README would be beneficial.

[flyq]

I fixed this by

sudo apt install libsqlite3-dev

[Piping]

@flyq Thanks.