Add migration command in CLI

CHANGELOG.md

@@ -14,7 +14,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Server` API has changed. Renamed `Quiet` to `Stop`. Renamed `Stop` to `Shutdown`. _Note:_ As a result of this renaming, the behavior of `Stop` has changed. Please update the exising code to call `Shutdown` where it used to call `Stop`.
 - `Scheduler` API has changed. Renamed `Stop` to `Shutdown`.
 - Requires redis v4.0+ for multiple field/value pair support
-- Renamed pending key (TODO: need migration script)
 - `Client.Enqueue` now returns `TaskInfo`
 - `Inspector.RunTaskByKey` is replaced with `Inspector.RunTask`
 - `Inspector.DeleteTaskByKey` is replaced with `Inspector.DeleteTask`

internal/rdb/inspect.go

@@ -994,7 +994,7 @@ else
 	end
 end
 local unique_key = redis.call("HGET", KEYS[1], "unique_key")
-if unique_key ~= nil and unique_key ~= "" and redis.call("GET", unique_key) == ARGV[1] then
+if unique_key and unique_key ~= "" and redis.call("GET", unique_key) == ARGV[1] then
 	redis.call("DEL", unique_key)
 end
 return redis.call("DEL", KEYS[1])
@@ -1094,7 +1094,7 @@ local ids = redis.call("ZRANGE", KEYS[1], 0, -1)
 for _, id in ipairs(ids) do
 	local task_key = ARGV[1] .. id
 	local unique_key = redis.call("HGET", task_key, "unique_key")
-	if unique_key ~= nil and unique_key ~= "" and redis.call("GET", unique_key) == id then
+	if unique_key and unique_key ~= "" and redis.call("GET", unique_key) == id then
 		redis.call("DEL", unique_key)
 	end
 	redis.call("DEL", task_key)

internal/rdb/rdb.go

@@ -32,6 +32,11 @@ func (r *RDB) Close() error {
 	return r.client.Close()
 }
 
+// Client returns the reference to underlying redis client.
+func (r *RDB) Client() redis.UniversalClient {
+	return r.client
+}
+
 // Ping checks the connection with redis server.
 func (r *RDB) Ping() error {
 	return r.client.Ping().Err()