Problem: The Lndr DB has a unique constraint on channel_id in the push_data table that throws a 500 error when a user tries to register a new channel_id
Solution: Change the primary key of the push_data table and modify the upsert query to allow a user to have multiple channel_ids.
No concerns
Before merging, the new migration file should be run: lndr-backend/db/migrations/2018-10-08T10.00.00Z_change_push_data_pk.sql
lndr-backend/db/migrations/2018-10-08T10.00.00Z_change_push_data_pk.sql