Size and evolution of current cities present a great challenge to their inhabitants to make them develop in a harmonious and sustainable way. People living in large cities find many obstacles to participate in the urban development decisions affecting them directly. A tool which supports citizens in gathering, combining and visualizing the information, as well as proposing, discussing and selecting the best ideas for urban improvement would certainly help them to accomplish this task, thus contributing to the development of a more participatory society and a smarter city with better reaction capabilities to changes in the environment. In this work we present a smart city application, intended for citizens living in an urban community enabling them to present and share their opinions, comments and interests. The application also should support citizens to make decisions. Those decisions should influence local authorities concerning community improvements. The application may be used with any subject relevant to an urban community and thus, it could be useful in many scenarios of citizens' participation and decision making. It includes multiple views: time-based, spatial and relational.