Add a way to register routes that should be run by the bot on update.

src/telepathy/bot.cr

@@ -8,6 +8,8 @@ module Telepathy
             @this_user = get_me
             @last_update_id = uninitialized Int64?
             @last_update_id = nil
+            @command_hooks = {} of String => Update, Array(String) -> String
+            @message_hooks = [] of Update -> String
         end
 
         def get_me
@@ -26,5 +28,13 @@ module Telepathy
             updates.last?.try { |update| @last_update_id = update.update_id + 1 }
             return updates
         end
+
+        def command(command_name, &block: Update, Array(String) -> String)
+            @command_hooks[command_name] = block
+        end
+
+        def message(&block: Update -> String)
+            @message_hooks.push(block)
+        end
     end
 end