Include specific commands to run the D2RML transformation

[jakubklimek]

How, we have a generic command for running the docker version of D2RML and then we have sections for individual datasets. However, I as a user do not know how exactly should I set the parameters in the individual cases.

Could we have specific docker commands for each of the processed datasets, possibly including the necessary Turtle files in this repo? I think we discussed that this way, the mapping may not be the most up to date, but then we can have 2 commands - one with the "cached" turtle files from the repo and one with the direct link to the most up to date file.

[achort]

We have added two examples of using D2RML, that hopefully help clarify the use.

[jakubklimek]

@achort It clarifies it a bit, but still, could we make a snapshot of the mappings to be hosted here on GitHub so that the examples are not reliant on the availability of NTUA's servers? e.g. instead of https://stirdata-semantic.ails.ece.ntua.gr/api/content/el/mapping/bdd4413c-45ec-47b8-b25a-56880a0a0b6e we could have this turtle file persisted somewhere in this repo?