code: def get_files(self):
          
          files = {}
          for filename in os.listdir(self.source):
              path = os.path.join(self.source, filename)
              files[filename] = frontmatter.load(path, 
                  filename=filename, 
                  slug=os.path.splitext(filename)[0])
  
          return files
docs: Read and parse files from a directory,
          return a dictionary of path => post