Add new feature markdown to HTML

[mkim219]

This pull request fixes #18

Change

markDownToHTML function

• created new function called "markDownToHTML"
• takes one string arguments and return string.
• includes set of regex for replacing markdown syntax to HTML tag
• the input string goes through the regex and replace into HTML tag if string contains corresponding markdown syntax
• function returns trimmed string

createHTML function

• already existing function
• need to validate the extension of the file by using if-else statement
• if the input file is md file, using "makrDownToHTML" to convert from markdown string to HTML string and store dataTemplate variable
• variable dataTemplate places in inside of body tag

cli function

• has validation for accepting only text file
• add md extension file in else if statement

README.md

• describe new feature

[suhhee1011]

Hi! Minsu, I have reviewed your PR. And I found a few things that if you fixed them, it will be better.

• Please add a feature to convert both text and MD files in one folder to HTML.
• Please fix that if I put Read.md in the folder with text files, it shows an error message "This README.txt file is not exist. Please check file name"

[mkim219]

I have fixed those issue. Please review and confirm.

[suhhee1011]

Thank you it looks good to me!