Explain in README how to take advantage of substitutions
Explain in README how to take advantage of substitutions

Rhinofly/config-ordered,jasonchaffee/config,twitter-forks/config,rmuhamedgaliev/config,melrief/config,zeq9069/config,yvvq/config,leakingtapan/config,melrief/config,fpringvaldsen/config,meln1k/config,cprice404/config,malexandert/config,chris-martin/hocon-python,Applied-Duality/config,roznalex/config,twitter-forks/config,malexandert/config,typesafehub/config,Applied-Duality/config,zeq9069/config,shrutig/config,Kaliber/config-ordered,wmudge/config,wmudge/config,cprice404/config,roznalex/config,fpringvaldsen/config,yvvq/config,Rhinofly/config-ordered,rmuhamedgaliev/config,typesafehub/config,Kaliber/config-ordered,jasonchaffee/config,leakingtapan/config,shrutig/config,meln1k/config,chris-martin/hocon-python