stoa-plugin: allow mass assignment for usp_id and invitation_code
stoa-plugin: allow mass assignment for usp_id and invitation_code

  Both attributes can be set by the user on signup so we should allow
  mass assignment.

tallysmartins/noosfero,vfcosta/noosfero,coletivoEITA/noosfero,coletivoEITA/noosfero,larissa/noosfero,marcosronaldo/noosfero,hebertdougl/noosfero,AlessandroCaetano/noosfero,coletivoEITA/noosfero,coletivoEITA/noosfero,tallysmartins/noosfero,blogoosfero/noosfero,hebertdougl/noosfero,hebertdougl/noosfero,evandrojr/noosferogov,EcoAlternative/noosfero-ecosol,uniteddiversity/noosfero,abner/noosfero,tallysmartins/noosfero,evandrojr/noosferogov,samasti/noosfero,CIRANDAS/noosfero-ecosol,macartur/noosfero,alexandreab/noosfero,samasti/noosfero,abner/noosfero,uniteddiversity/noosfero,tallysmartins/noosfero,marcosronaldo/noosfero,arthurmde/noosfero,EcoAlternative/noosfero-ecosol,macartur/noosfero,evandrojr/noosferogov,vfcosta/noosfero,blogoosfero/noosfero,blogoosfero/noosfero,arthurmde/noosfero,larissa/noosfero,abner/noosfero,macartur/noosfero,macartur/noosfero,samasti/noosfero,vfcosta/noosfero,evandrojr/noosferogov,coletivoEITA/noosfero-ecosol,AlessandroCaetano/noosfero,larissa/noosfero,marcosronaldo/noosfero,EcoAlternative/noosfero-ecosol,evandrojr/noosfero,vfcosta/noosfero,macartur/noosfero,arthurmde/noosfero,alexandreab/noosfero,samasti/noosfero,uniteddiversity/noosfero,samasti/noosfero,larissa/noosfero,alexandreab/noosfero,samasti/noosfero,blogoosfero/noosfero,evandrojr/noosferogov,AlessandroCaetano/noosfero,AlessandroCaetano/noosfero,abner/noosfero,CIRANDAS/noosfero-ecosol,EcoAlternative/noosfero-ecosol,CIRANDAS/noosfero-ecosol,tallysmartins/noosfero,evandrojr/noosferogov,LuisBelo/tccnoosfero,EcoAlternative/noosfero-ecosol,arthurmde/noosfero,LuisBelo/tccnoosfero,coletivoEITA/noosfero-ecosol,uniteddiversity/noosfero,alexandreab/noosfero,evandrojr/noosfero,LuisBelo/tccnoosfero,blogoosfero/noosfero,uniteddiversity/noosfero,larissa/noosfero,AlessandroCaetano/noosfero,coletivoEITA/noosfero-ecosol,coletivoEITA/noosfero,blogoosfero/noosfero,hebertdougl/noosfero,hebertdougl/noosfero,abner/noosfero,macartur/noosfero,abner/noosfero,coletivoEITA/noosfero,alexandreab/noosfero,hebertdougl/noosfero,blogoosfero/noosfero,hebertdougl/noosfero,tallysmartins/noosfero,LuisBelo/tccnoosfero,evandrojr/noosfero,evandrojr/noosfero,marcosronaldo/noosfero,alexandreab/noosfero,EcoAlternative/noosfero-ecosol,arthurmde/noosfero,larissa/noosfero,macartur/noosfero,vfcosta/noosfero,coletivoEITA/noosfero-ecosol,larissa/noosfero,LuisBelo/tccnoosfero,uniteddiversity/noosfero,EcoAlternative/noosfero-ecosol,coletivoEITA/noosfero-ecosol,tallysmartins/noosfero,evandrojr/noosfero,uniteddiversity/noosfero,CIRANDAS/noosfero-ecosol,marcosronaldo/noosfero,evandrojr/noosfero,arthurmde/noosfero,vfcosta/noosfero,marcosronaldo/noosfero,AlessandroCaetano/noosfero,coletivoEITA/noosfero,alexandreab/noosfero,LuisBelo/tccnoosfero,evandrojr/noosferogov,CIRANDAS/noosfero-ecosol,coletivoEITA/noosfero-ecosol,arthurmde/noosfero,abner/noosfero,AlessandroCaetano/noosfero,evandrojr/noosfero,marcosronaldo/noosfero