Metadata Factoring

[MikeInnes]

Just leaving a note on some things we discussed earlier. Right now in the Types module there's some repetition of fields like description, tags etc. Some of these are essential data about the object and some are essentially metadata that might be useful for searching or browsing lessons. It might be useful to factor this explicitly as follows:

type Metadata
  description::String
  tags::Vector{String}
  # ...
end

type Lesson
  name::String
  meta::Metadata
  # ...
end

It might even make sense to dump the typing entirely and just have meta::Dict{Any,Any}. It may be more convenient if metadata is optional, and especially if new metadata can be added and stored without causing issues. Plus, it might be nice for descriptions and things to be markdown objects.