Fixed post duplication issue when syndicating back to source site.

[chetansatasiya]

Fixes #127

[philipjohn]

Thanks for this @chetansatasiya ! Can I ask you to provide an overview of what the code here does please?

[philipjohn]

Looking over this code again @chetansatasiya I'm thinking that the using an API endpoint might be more processing than is really necessary.

Instead, I'm wondering about having each post contain a piece of meta with an array of sites it has passed through. This meta would get passed on as the post is syndicated through multiple sites, with each site adding itself to the array.

If at any point a site finds itself in that array, it would skip syndicating that post to avoid the duplicate.