feat: publish standalone worker

Separate worker packaging and service lifecycle from the control plane.

app/models/payment.go

@@ -0,0 +1,18 @@
+package models
+
+import "rsgit.ru/rsmon/rsmon/app/models/concerns"
+
+// Payment provides functionality.
+type Payment struct {
+	concerns.Model
+
+	AccountID int64 `json:"account_id"`
+	Account   User  `json:"-"`
+
+	Kind   string
+	ExtID  string
+	Amount int
+
+	concerns.Timestamped
+	Audited
+}