Merge branch 'fix/documents-keyerror' into 'master'

Ghost User
2018-03-22T13:08:48+01:00

Fix KeyError in documents package

See merge request thalia/concrexit!774

(cherry picked from commit fa4f54d3a7666993584ae5925a6ab3a1685192d4)

2835f036 Fix KeyError in documents package