tenant_kit

https://github.com/wintan1418/tenant_kit

TenantKit makes a Rails app multi-tenant using the row-level / shared-schema strategy: one database, a tenant_id foreign key on owned tables, automatic query scoping via ActiveSupport::CurrentAttributes, auto-assignment of the current tenant, and first-class tenant propagation into ActiveJob background jobs. It is strict by default: querying a tenant-scoped model with no tenant set raises rather than leaking another tenant's data.