fix(docs/app.md): Arrgegate -> Aggregate
fix(docs/app.md): Arrgegate -> Aggregate

mpraglowski/rails_event_store,arkency/rails_event_store,RailsEventStore/rails_event_store,RailsEventStore/rails_event_store,mpraglowski/rails_event_store,RailsEventStore/rails_event_store,arkency/rails_event_store,RailsEventStore/rails_event_store,mpraglowski/rails_event_store,arkency/rails_event_store,mpraglowski/rails_event_store,arkency/rails_event_store