Storing data as a sequence of events - RubyConfAt lightning talk supplement

An introduction to event sourcing as a persistence technique for Ruby/Rails applications, based on a RubyConfAt lightning talk. Covers core concepts: events as immutable facts, streams as logical groupings of events, and projections for rebuilding state. Addresses four common misconceptions — that immutability prevents data correction, that rebuilding state requires loading all history, that it's slow, and that it requires new infrastructure. Highlights RailsEventStore as a drop-in gem supporting PostgreSQL, MySQL, and SQLite. Emphasizes event sourcing as a useful tool for auditable, debuggable systems, not a universal solution.