Dflip Plugin TypeError

Question

So I've been trying to add Dflip Jquery Plugin in my ruby on rails application but I am getting an Uncaught Type error

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while working on this error I got to know that it's not able to read my dFlipLocation as well. I am really new to ruby on rails and I don't know what's the reason for not being able to detect dFlipLocation.

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this is the link of the github repo where you can go through files and code

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and this is structure of my Rails app