update

1. add cron module
2. add pool module
3. add tcgplayer background job
4. add card price model

modules/pool/pool.go

@@ -0,0 +1,38 @@
+package pool
+
+import "sync"
+
+// Pool -
+type Pool struct {
+	queue chan bool
+	wg    *sync.WaitGroup
+}
+
+// NewPool -
+func NewPool(size int) *Pool {
+	if size < 1 {
+		size = 1
+	}
+	p := &Pool{
+		queue: make(chan bool, size),
+		wg:    &sync.WaitGroup{},
+	}
+	return p
+}
+
+// Add -
+func (p *Pool) Add() {
+	p.queue <- true
+	p.wg.Add(1)
+}
+
+// Done -
+func (p *Pool) Done() {
+	<-p.queue
+	p.wg.Done()
+}
+
+// Wait -
+func (p *Pool) Wait() {
+	p.wg.Wait()
+}