don't serialize empty vecs

src/command.rs

@@ -10,14 +10,18 @@ use tracing::{debug, error, info, trace};
 #[derive(Serialize)]
 struct Server {
     channels: Vec<Channel>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
     orphanage: Vec<GuildChannel>,
+    #[serde(skip_serializing)]
     needs_clean: bool,
 }
 
 #[derive(Serialize)]
 struct Channel {
     this: GuildChannel,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
     children: Vec<Channel>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
     messages: Vec<Message>,
 }