There are a number of ways that a restaurant might benefit a community.
On one level, it might help the community if you open a restaurant that serves healthy foods. This could help individuals remain healthier. It could also help to reduce the costs that the community incurs for health care.
On a more obvious level, your restaurant, if sited in the right place, could help the community economically. Communities can thrive if they have pockets of economic activity where the various shops and restaurants draw customers that might then patronize other shops and restaurants. These pockets of economic activity become major draws for the community. Apartment buildings might be built near to such pockets so that people could live near to them, for example. Thus, by opening a restaurant, you might be helping your community to create a solid pocket of economic activity that can become the core for a neighborhood (sometimes called an "urban village").