feat: add river jobs

contracts/cron_job.go

@@ -0,0 +1,15 @@
+package contracts
+
+import (
+	"time"
+
+	"github.com/riverqueue/river"
+)
+
+type CronJob interface {
+	Description() string
+	Periodic() time.Duration
+	JobArgs() river.JobArgs
+	InsertOpts() *river.InsertOpts
+	RunOnStart() bool
+}