Dear Mohamed
as I've already told you, we can't currently merge the support for an additional triplestore, since it would add significant maintenance effort to us. However, you can experiment with AllegroGraph on your own, and maybe if we will see the code stable enough and required by many users, we could reconsider merging it.
As I first step, I suggest to you to fork the repository of Semantic Turkey, and create a branch to place your modifications. Doing this, it would be simpler for us to understand what you did and whether a simple extension would sufficient. Indeed, the modification of STLocalReposutory can't be bundled in an extension, but perhaps it is not required.
Best Regards,
Manuel Fiorelli