Add some comments to relation plugin
Add some comments to relation plugin

latin-language-toolkit/arethusa,latin-language-toolkit/arethusa,PonteIneptique/arethusa,PonteIneptique/arethusa,alpheios-project/arethusa,alpheios-project/arethusa,alpheios-project/arethusa,fbaumgardt/arethusa,Masoumeh/arethusa,fbaumgardt/arethusa,Masoumeh/arethusa,fbaumgardt/arethusa