Improve README.md and add CONTRIBUTING.md file (apache#51)

Signed-off-by: xiaolong.ran <[email protected]>

Improve README.md and add CONTRIBUTING.md file.

.header

@@ -0,0 +1,16 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.

CONTRIBUTING.md

@@ -0,0 +1,86 @@
+<!--
+
+    Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing,
+    software distributed under the License is distributed on an
+    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+    KIND, either express or implied.  See the License for the
+    specific language governing permissions and limitations
+    under the License.
+
+-->
+
+# How to contribute
+
+If you would like to contribute code to this project you can do so through GitHub by forking the repository and sending a pull request.
+
+This document outlines some of the conventions on development workflow, commit message formatting, contact points and other resources to make it easier to get your contribution accepted.
+
+## Steps to Contribute
+
+Since the `go mod` package management tool is used in this project, your go version is required at **Go1.11+**.
+
+### Fork
+
+Before you start contributing, you need to fork [pulsar-client-go](https://github.com/apache/pulsar) to your github repository.
+
+### Installation
+
+If you don't currently have a go environment installed，install Go according to the installation instructions here: http://golang.org/doc/install
+
+##### mac os && linux
+
+```bash
+$ mkdir -p $HOME/github.com/apache/
+$ cd $HOME/github.com/apache/
+$ git clone [email protected]:[your-github-id]/pulsar-client-go.git
+$ cd pulsar-client-go
+$ go mod download
+```
+
+When you execute `go mod download`, there may be some libs that cannot be downloaded. You can download them by referring to the proxy provided by [GOPROXY.io](https://goproxy.io/).
+
+### Contribution flow
+
+```bash
+$ git remote add apache [email protected]:apache/pulsar-client-go.git
+
+// sync with remote master
+$ git checkout master
+$ git fetch apache
+$ git rebase apache/master
+$ git push origin master
+
+// create PR branch
+$ git checkout -b your_branch   
+# do your work, and then
+$ git add [your change files]
+$ git commit -sm "xxx"
+$ git push origin your_branch
+```
+
+Thanks for your contributions!
+
+#### Code style
+
+The coding style suggested by the Golang community is used in Apache pulsar-client-go. See the [style doc](https://github.com/golang/go/wiki/CodeReviewComments) for details.
+
+Please follow this style to make your pull request easy to review, maintain and develop.
+
+#### Create new file
+
+The project uses the open source protocol of Apache License 2.0. When you need to create a new file when developing new features, 
+please add it at the beginning of the file. The location of the header file: [header file](.header).
+
+#### Updating dependencies
+
+Apache `pulsar-client-go` uses [Go 1.11 module](https://github.com/golang/go/wiki/Modules) to manage dependencies. To add or update a dependency: use the `go mod edit` command to change the dependency.

README.md

@@ -24,9 +24,7 @@
 [![LICENSE](https://img.shields.io/hexpm/l/pulsar.svg)](https://github.com/apache/pulsar-client-go/blob/master/LICENSE)
 # Apache Pulsar Go Client Library
 
-> Note: this library is still a work in progress. For production usage, please
-refer to the CGo based client library, documented at
-http://pulsar.apache.org/docs/en/client-libraries-go/
+A Go client library for the [Apache Pulsar](https://pulsar.incubator.apache.org/) project.
 
 ## Goal
 
@@ -36,6 +34,10 @@ depend on the C++ Pulsar library.
 Once feature parity and stability are reached, this will supersede the current
 CGo based library.
 
+## Requirements
+
+- Go 1.11+
+
 ## Status
 
 Check the Projects page at https://github.com/apache/pulsar-client-go/projects for
@@ -49,11 +51,15 @@ Import the client library:
 import "github.com/apache/pulsar-client-go/pulsar"
 ```
 
+Create a Producer:
+
 ```go
 client, err := pulsar.NewClient(pulsar.ClientOptions{
     URL: "pulsar://localhost:6650",
 })
 
+defer client.Close()
+
 producer, err := client.CreateProducer(pulsar.ProducerOptions{
 	Topic: "my-topic",
 })
@@ -62,13 +68,45 @@ err = producer.Send(context.Background(), &pulsar.ProducerMessage{
 	Payload: []byte("hello"),
 })
 
-if err == nil {
-	fmt.Println("Published message")
-} else {
-	fmt.Println("Failed to publish message", err)
+defer producer.Close()
+
+if err != nil {
+    fmt.Println("Failed to publish message", err)
 }
+fmt.Println("Published message")
+```
+
+Create a Consumer:
+
+```go
+client, err := pulsar.NewClient(pulsar.ClientOptions{
+    URL: "pulsar://localhost:6650",
+})
+
+defer client.Close()
+
+consumer, err := client.Subscribe(pulsar.ConsumerOptions{
+        Topic:            "my-topic",
+        SubscriptionName: "my-sub",
+        Type:             pulsar.Shared,
+    })
+
+defer consumer.Close()
+
+msg, err := consumer.Receive(context.Background())
+    if err != nil {
+        log.Fatal(err)
+    }
+
+fmt.Printf("Received message msgId: %#v -- content: '%s'\n",
+            msg.ID(), string(msg.Payload()))
+
 ```
 
+## Contributing
+
+Contributions are welcomed and greatly appreciated. See [CONTRIBUTING.md](CONTRIBUTING.md) for details on submitting patches and the contribution workflow.
+
 ## Contact
 
 ##### Mailing lists
@@ -87,5 +125,3 @@ You can self-register at https://apache-pulsar.herokuapp.com/
 ## License
 
 Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0
-
-