Building and returning JWTs on login

* Created Util package for assorted items
* Currently generates an HMAC key on startup, to be changed
* JWT also includes login role

util/util.go

@@ -0,0 +1,12 @@
+package util
+
+import "crypto/rand"
+
+func GenerateHmac() []byte {
+	b := make([]byte, 64)
+	if _, err := rand.Read(b); err != nil {
+		panic(err)
+	}
+
+	return b
+}