add promise joke

Not sure how to format it. Here was the original, for reference:

```
07:54 < porchrat> anyone awake?
07:54 < porchrat> aaaallllllliiiiiiiiveeeee
08:06 -!- Netsplit over, joins: daira
08:07 -!- gkatsev [~gkatsev@oftn/board/gkatsev] has joined #promises
08:10 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has quit
          [Ping timeout: 252 seconds]
09:16 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has joined
          #promises
09:34 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has quit
          [Ping timeout: 246 seconds]
09:37 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has joined
          #promises
09:42 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has quit
          [Ping timeout: 246 seconds]
09:45 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has joined
          #promises
09:50 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has quit
          [Ping timeout: 240 seconds]
10:07 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has joined
          #promises
10:15 -!- NotMyself [~NotMyself@c-76-104-208-159.hsd1.wa.comcast.net] has joined
          #promises
10:39 < terinjokes> porchrat: nope
10:39 < terinjokes> we all died
10:39 < terinjokes> i promise
10:53 -!- dcherman [~dcherman@ool-4356093e.dyn.optonline.net] has joined #promises
11:29 -!- NotMyself [~NotMyself@c-76-104-208-159.hsd1.wa.comcast.net] has quit [Quit:
          My MacBook Pro has gone to sleep. ZZZzzz…]
11:46 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has quit
          [Ping timeout: 246 seconds]
11:48 -!- daira [~daira@host86-153-60-174.range86-153.btcentralplus.com] has joined
          #promises
11:53 < porchrat> damn
11:53 < porchrat> terrible joke
12:10 < spion> :)
```