Update docs with new APIs

CHANGELOG.md

@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- `Background` type is renamed to `Server`.
+  - To upgrade from the previous version, Update `NewBackground` to `NewServer` and pass `Config` by value.
+- New `Server` type exposes `Start`, `Stop`, and `Quiet` as well as `Run`.
+- CLI is renamed to `asynq`.
+  - To upgrade to the latest version run `go get -u github.com/hibiken/tools/asynq`
+- The `ps` command in CLI is renamed to `servers`
+
 ## [0.7.1] - 2020-04-05
 
 ### Fixed

README.md

@@ -161,8 +161,8 @@ func main() {
 }
 ```
 
-Next, create a binary to process these tasks in the background.  
-To start the background workers, use [`Background`](https://pkg.go.dev/github.com/hibiken/asynq?tab=doc#Background) and provide your [`Handler`](https://pkg.go.dev/github.com/hibiken/asynq?tab=doc#Handler) to process the tasks.
+Next, create a work server binary to process these tasks in the background.  
+To start the background workers, use [`Server`](https://pkg.go.dev/github.com/hibiken/asynq?tab=doc#Server) and provide your [`Handler`](https://pkg.go.dev/github.com/hibiken/asynq?tab=doc#Handler) to process the tasks.
 
 You can optionally use [`ServeMux`](https://pkg.go.dev/github.com/hibiken/asynq?tab=doc#ServeMux) to create a handler, just as you would with [`"net/http"`](https://golang.org/pkg/net/http/) Handler.
 
@@ -179,7 +179,7 @@ const redisAddr = "127.0.0.1:6379"
 func main() {
     r := &asynq.RedisClientOpt{Addr: redisAddr}
 
-    bg := asynq.NewBackground(r, &asynq.Config{
+    srv := asynq.NewServer(r, asynq.Config{
         // Specify how many concurrent workers to use
         Concurrency: 10,
         // Optionally specify multiple queues with different priority.
@@ -197,7 +197,7 @@ func main() {
     mux.HandleFunc(tasks.ImageProcessing, tasks.HandleImageProcessingTask)
     // ...register other handlers...
 
-    bg.Run(mux)
+    srv.Run(mux)
 }
 ```
 

doc.go

@@ -30,13 +30,13 @@ Task is created with two parameters: its type and payload.
     // Schedule the task to be processed in one minute.
     err = client.EnqueueIn(time.Minute, t)
 
-The Background is used to run the background task processing with a given
+The Server is used to run the background task processing with a given
 handler.
-    bg := asynq.NewBackground(redis, &asynq.Config{
+    srv := asynq.NewServer(redis, asynq.Config{
         Concurrency: 10,
     })
 
-    bg.Run(handler)
+    srv.Run(handler)
 
 Handler is an interface with one method ProcessTask which
 takes a task and returns an error. Handler should return nil if