Add /last_aired route

For @ask-compu

README.md

@@ -64,6 +64,11 @@ objects as defined above.
 
 Returns the episode of My Little Pony: Friendship is Magic that will air next.
 
+### `/last_aired`
+
+Returns the episode of My Little Pony: Friendship is Magic that most recently
+aired.
+
 ### `/season/<number>`
 
 Returns all information about episodes in the given season number or a `404`

ponyapi.nim

@@ -85,6 +85,20 @@ routes:
   get "/random":
     resp Http200, myHeaders, pretty(%%episodes.randomChoice(), 4)
 
+  get "/last_aired":
+    var
+      now = getTime()
+      ep: Episode
+
+    for epid, episode in pairs[Episode](episodes):
+      var then = times.fromSeconds(episode.air_date)
+
+      if now < then:
+        ep = episodes[epid-1]
+        break
+
+    resp Http200, myHeaders, pretty(%%ep, 4)
+
   get "/season/@snumber":
     var
       season: int = @"snumber".parseInt