nomsfs blog: final schema

nomsfs final schema

struct Filesystem {
     root: struct Inode {
          attr: struct Attr { /* e.g. permissions, modification time, etc. */ }
          contents: Union {
               struct File { data: Ref<Blob> /* Noms pile of bytes */ } |
               struct Directory: { contents: Map<string, Cycle<1>> }
          }
     }
}