There was  a typo in the gorm migration that creates the pinned events and the default values are not explicitly stated.  Luckily, the default values that were attempted to be set are the implicit defaults for those data types.  Still, since there was an attempt to explicitly set them, we should correct that failed attempt.

Definition of Done: A new migration needs to be created that alters the events table to set the default value of `pinned_at` to NULL and `pinned` to false.  The existing migration shouldn't be altered.