Config: Reload configuration on modification

It detects changes on the config.yml automtically if invidious is
running on linux. If not, the configuration can be reloaded using
`kill -s HUP $(pidof invidious)` or any other tool that sends a SIGHUP
signal to the invidious process.

Closes #16

shard.lock

@@ -20,6 +20,10 @@ shards:
     git: https://github.com/crystal-loot/exception_page.git
     version: 0.2.2
 
+  inotify:
+    git: https://github.com/petoem/inotify.cr.git
+    version: 1.0.3
+
   kemal:
     git: https://github.com/kemalcr/kemal.git
     version: 1.1.2