Recommend adding a link to GERBIL in entity_linking.md

[munnellg]

GERBIL in general is just a really good entry point for people interested in Entity Linking.

There are issues with inscrutability e.g. can't see what candidates were considered/rejected by an EL service, you don't actually get to see the annotations returned by the EL system. Only the final stats as generated by GERBIL. However, it is a recognised bench marking platform that should definitely be in anyone's toolbox if they are interested in EL.

Website here: http://gerbil.aksw.org/gerbil/

Paper here: http://www.www2015.it/documents/proceedings/proceedings/p1133.pdf

[sebastianruder]

That's a great reference. Would you mind adding it to the entity linking file, so that people can find it more easily?

[sebastianruder]

Added in #62.