Add foreign key on event
#4 (closed) was closed, but some fields still need foreign key on event:
type Transfer @entity {
blockNumber: Int! @index
→ event (not sure if needed since we already copied the timestamp)
type ChangeOwnerKey @entity {
blockNumber: Int!
→ event
type Cert @entity {
createdOn: Int!
→ event (createdIn)
expireOn: Int!
→ optional event (expireIn)
type SmithCert @entity {
createdOn: Int!
→ event (createdIn)