Can you explain to the uninitiated, what does Redis do for you in this stack? I read the whole chapter on it in "Seven Databases" but it just didn't click for me what Redis is for. Pardon my ignorance.
redis is an in-memory(with persistence) data-structures server,
do you need a set,increment,get+put,cache(like memcache),hyperloglog,list,hashes,bitarray,sorted_list + custom_lua_functions that you want to access from multiple web-servers ?
Then Ansible, Git, Nginx, Varnish, Redis, Angular and Bootstrap. And CloudFlare for DNS/CDN/optimization/DDoS protection.