feat: add dig command

Other changes:
- use middleware for permission checking
- able to respond with emoji
- log incoming requests

utils/utils.go

@@ -0,0 +1,18 @@
+package utils
+
+func WaitFor(fn func()) <-chan struct{} {
+	ch := make(chan struct{})
+	go func() {
+		defer close(ch)
+		fn()
+	}()
+	return ch
+}
+
+func ToLookupMap[T comparable](s []T) map[T]struct{} {
+	m := make(map[T]struct{}, len(s))
+	for _, item := range s {
+		m[item] = struct{}{}
+	}
+	return m
+}