adding map

[Salik147]

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Describe your change: I have added an algorithm called map in Data-Structures directory

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

Checklist:

• [Y ] I have read CONTRIBUTING.md.
• [Y ] This pull request is all my own work -- I have not plagiarized.
• [Y ] I know that pull requests will not be merged if they fail the automated tests.
• [Y ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [Y ] All new JavaScript files are placed inside an existing directory.
• [Y ] 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
• [Y ] All new algorithms have a URL in their comments that points to Wikipedia or another similar explanation.
• [Y ] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[appgurueu]

Sorry, but there is no meaningful implementation of an algorithm or data structure here.