Modify README_enUS.md, add client registration, design goals and online trial.

README_enUS.md

@@ -29,13 +29,25 @@ Well, PowerJob is there for you, it is the choice of a new generation. It is a p
 -   Quick failover and recovery support: Whenever any task failed, PowerJob server would retry according to the configured strategy. As long as there were enough nodes in the cluster, the failed tasks could execute successfully finally.
 -   Convenient to run and maintain: PowerJob supports online logging. Logs generated by the worker would be transferred and displayed on the console instantly, therefore reducing the cost of debugging and improving the efficiency significantly.
 
-### Applicable scene
+### Applicable scenes
 
 -   Scenarios with timed tasks: such as full synchronization of data at midnight, generating business reports at desired time.
 -   Scenarios that require all machines to run tasks simultaneously: such as log cleanup.
 -   Scenarios that require distributed processing: For example, a large amount of data requires updating, while the stand-alone execution takes quite a lot of time. The Map/MapReduce mode could be applied in which the workers would join the cluster for PowerJob server to dispatch, to speed up the time-consuming process, therefore improving the computing ability of the whole cluster.
+-   Scenarios with delayed tasks: For instance, disposal of overdue orders.
 
-### Comparison of similar products
+### Design goals
+
+PowerJob aims to be an enterprise-level scheduling middleware. By deploying PowerJob-server as the scheduling center,
+all the applications could gain scheduling and distributed computing ability relying on PowerJob-worker.
+
+### Online trial
+
+Trial address: [Online Trial Address](http://try.powerjob.tech/)  
+Application name: powerjob-agent-test  
+Application password: 123
+
+### Comparison with similar products
 
 |                                    | QuartZ                                                    | xxl-job                                                   | SchedulerX 2.0                                               | PowerJob                                                |
 | ---------------------------------- | --------------------------------------------------------- | --------------------------------------------------------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
@@ -54,6 +66,14 @@ Well, PowerJob is there for you, it is the choice of a new generation. It is a p
 
 **[中文文档](https://www.yuque.com/powerjob/product)**
 
+# User Registration
+[Click to register as PowerJob client and contribute to PowerJob!](https://github.com/KFCFans/PowerJob/issues/6)  
+ღ( ´・ᴗ・\` )ღ Many thanks to the following registered clients. ღ( ´・ᴗ・\` )ღ
+<p style="text-align: center">
+<img src="https://raw.githubusercontent.com/KFCFans/PowerJob/master/others/images/user.png" alt="PowerJob User" title="PowerJob User"/>
+</p>
+
+
 # Others
 
 -   PowerJob is permanently open source software(Apache License, Version 2.0), please feel free to try, deploy and put into production!