fixed scheduler build error and added drone config

.drone.yml

@@ -0,0 +1,10 @@
+---
+kind: pipeline
+name: default
+
+steps:
+- name: build library
+  image: golang
+  commands:
+  - go test
+  - go build

scheduler.go

@@ -1,7 +1,6 @@
 package gtq
 
 import (
-	"fmt"
 	"sort"
 	"time"
 )