Update pushmirror model to allow sync-on-push

Author: harryzcy

models/repo/pushmirror.go

@@ -23,6 +23,7 @@ type PushMirror struct {
 	Repo       *Repository `xorm:"-"`
 	RemoteName string
 
+	SyncOnPush     bool
 	Interval       time.Duration
 	CreatedUnix    timeutil.TimeStamp `xorm:"created"`
 	LastUpdateUnix timeutil.TimeStamp `xorm:"INDEX last_update"`