Copyright violation in Users/Docker_Image.rst

Added citation source and cited without any change
Closes #482

Author: acashmkj

Diff for: Users/Docker_Image.rst

@@ -3,19 +3,21 @@ What is Docker?
 
 Docker is a tool designed to make it easier to create, deploy, and run
 applications by using containers. Containers allow a developer to package
-up an application with all of the parts it needs, like libraries and other
-dependencies, and ship it all out as a single package.
-
-With the help of containers, the developer can rest assured that
-the application will run on other machines regardless of any
-customized settings his machine might have that could differ from the
-machine used for writing and testing the code.
-
-Unlike a virtual machine, rather than creating a whole virtual operating
-system, Docker allows applications to use the same kernel as the system
-that they're running on and only requires applications being shipped
-with things not already running on the host computer. This gives a
-significant performance boost and reduces the size of the application.
+up an application with all of the parts it needs, such as libraries and other
+dependencies, and ship it all out as one package. By doing so, thanks to the
+container, the developer can rest assured that the application will run
+on any other Linux machine regardless of any customized settings that
+machine might have that could differ from the machine used for writing
+and testing the code.
+
+In a way, Docker is a bit like a virtual machine. But unlike a virtual
+machine, rather than creating a whole virtual operating system, Docker
+allows applications to use the same Linux kernel as the system that
+they're running on and only requires applications be shipped with things
+not already running on the host computer. This gives a significant
+performance boost and reduces the size of the application.
+
+Cited from `opensource.com <https://opensource.com/resources/what-docker>`__.
 
 What is a Docker Image and how is it different from a container?
 ----------------------------------------------------------------