Existing Ruby on Rails project needs a developer for variable workload

Our existing Ruby on Rails project requires a developer to work on new features as and when required. We are looking for a mid-level developer who can work on an as-needed basis with a flexible schedule. The main priority for the developer is to work on new features. Bug fixes and optimization may also be required from time to time. We do not have specific deadlines for the new features, but a general timeline may be provided. The ideal candidate should have experience in Ruby on Rails and be able to work independently. Good communication skills and the ability to work collaboratively with our team are also essential.