Add log directory into config file.

configs/config.yaml

@@ -1,6 +1,7 @@
 listen_on: "tcp :29101"
 hash_salt: "iyP3oZWHI3xO3XBF7s78Vg"
 web_dir: "web"
+log_dir: "/var/log/dwelling-upload"
 uploads:
   directory: "/srv/uploads"
   limits:

internal/configuration/configuration.go

@@ -13,6 +13,7 @@ type Configuration struct {
 	ListenOn string `yaml:"listen_on"`
 	HashSalt string `yaml:"hash_salt"`
 	WebDir   string `yaml:"web_dir"`
+	LogDir   string `yaml:"log_dir"`
 	Uploads  struct {
 		Directory string `yaml:"directory"`
 		Limits    struct {