Add functionality to create and modify README.md file

[puresweep2]

Description

This PR adds functionality to the main.go file to create and modify the README.md file. If the README.md file does not exist, it creates a new file and appends the paragraph "This is an experimental project" to it. If the file already exists, it opens it in append mode and adds the paragraph to the end.

Summary of Changes

• Added a new function named "checkAndModifyReadme" to handle the creation and modification of the README.md file.
• The function checks if the README.md file exists in the root directory of the project.
• If the file does not exist, it creates a new README.md file.
• If the file exists, it opens it in append mode.
• The function writes the paragraph "This is an experimental project" to the README.md file.
• The function saves and closes the README.md file.
• Called the "checkAndModifyReadme" function in the main function of the program.

Please review and merge this PR. Thank you!

Fixes #5.

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[taherv]

Reset main.go

Don't generate any golang code. Just make the change requested in the issue by editing README.md file directly