My idea is to eventually sell it to local business
If by this you mean sell the software as a service that local businesses can pay for on a recurring basis, then I don't think open sourcing it will hinder you much there. Restaurants aren't well equipped to self-hosting open source applications, so you won't lose too much business in that regard.
If instead you mean sell the software as in the intellectual property to a local business... in this case I'd keep it proprietary because if it's open source they have no incentive to purchase it from you.
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It depends on what you mean by:
If by this you mean sell the software as a service that local businesses can pay for on a recurring basis, then I don't think open sourcing it will hinder you much there. Restaurants aren't well equipped to self-hosting open source applications, so you won't lose too much business in that regard.
If instead you mean sell the software as in the intellectual property to a local business... in this case I'd keep it proprietary because if it's open source they have no incentive to purchase it from you.