Add pry & shotgun to Gemfile
Move ParseCsv to lib/
Remove reference to ParseCsv from app.rb
Add new index for setting file path
Style form on index
Add sinatra-flash to Gemfile
Validate if file exists
Add error message to index page
Tidy/refactor app.rb & index.erb
Set path as session variable
Add titles and back button to /graphs
Clear session if file does not exist
Integrate Highstocks.js
Remove chartkick.js library
Convert to one-page view
Update README.md
Update README.md
Do not display error if no path given
Merge pull request #2 from DaveBlooman/feat/highcharts

[Review] Integrate Highcharts