added line number template
add line number to doc page, using doc-directive.js to handle all the changes with the DOM, refactor doc-service.js and doc-controller.js, add tab feature, add favicon.
fixed when create a new file in folder view, line number doesn't show
fixed when create a new file in folder view, line number doesn't show, and refactor doc-controller.js file
Adds github user authentication

gem install omniauth-github and dotenv-rails in development/test gem group

db:create and db:migrate of users table for omni auth

added github_omniauth.env file and added file path to .gitignore file

created new users table via rails generate resource. dropped previously created user table

added sessions controller

added omniauth functionality which returns correct user info from github

removed static login.html page and css. added class button to login link on root

completed user login functionality and sessions controller

removed all files and lines of code as per comments on pull request