initializing sub modules requires auth

**Describe the bug** I was fallowing the gut of how to use nix to compile the project and the part where . it tells you to use the command git submodule update --init --recursive requires a user name and password for wire-server-enterprise **To Reproduce** Steps to reproduce the behavior: 1. git clone https://github.com/wireapp/wire-server.git 2. git submodule update --init --recursive **Expected behavior** It should allow pulling the source since its needed for building from source