chore: add adr 8 to architecture readme

docs/architecture/README.md

@@ -31,6 +31,7 @@ To suggest an ADR, please make use of the [ADR template](./adr-template.md) prov
 | [002](./adr-002-go-module-versioning.md) | Go module versioning | Accepted |
 | [003](./adr-003-ics27-acknowledgement.md) | ICS27 acknowledgement format | Accepted |
 | [004](./adr-004-ics29-lock-fee-module.md) | ICS29 module locking upon escrow out of balance | Accepted |
+| [008](./adr-008-app-caller-cbs/adr-008-app-caller-cbs.md) | Callback to IBC ACtors | Accepted |
 | [015](./adr-015-ibc-packet-receiver.md) | IBC Packet Routing | Accepted |
 | [025](./adr-025-ibc-passive-channels.md) | IBC passive channels | Deprecated |
 | [026](./adr-026-ibc-client-recovery-mechanisms.md) | IBC client recovery mechansisms | Accepted |