Add --playground option to install generator
Add --playground option to install generator

This allows users to set up projects with GraphQL Playground as their IDE through the graphql_playground-rails gem

nevesenin/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby