added contributor graph to the readme

[dev-madhurendra]

 know more

Describe your change:

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new JavaScript files are placed inside an existing directory.
• All filenames should use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames.
  Example:UserProfile.js is allowed but userprofile.js,Userprofile.js,user-Profile.js,userProfile.js are not
• All new algorithms have a URL in their comments that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[appgurueu]

Why do we need this in the Readme? An excerpt of it is already visible in the sidebar, and users can click on that if they want to see more.

[dev-madhurendra]

Why do we need this in the Readme? An excerpt of it is already visible in the sidebar, and users can click on that if they want to see more.

Yeah, You are right but at left side we can see only few things and in readme we can see all the contributors. It is a way of thanking all the contributors.

[appgurueu]

I'm neutral on this.