Create dataset groups (tagging)

[sabas]

I'd like to have all datasets relating to an argument grouped together (eg: all datasets related to maritime transportation).
This could be done by adding tags as keywords in the datapackage.json and have pages on the website which can load list of datasets by keyword.
Example: http://data.okfn.org/data/keywords/container would load all datasets related to containers (container codes, IMDG code, and so on)