Rails migrations with database-specific data types
FYI for anyone who happens across this page, I fixed this by adding this (actually uncommenting it) to my Rails config:
config.active_record.schema_format = :sql
Have you tried specifying the type as a string instead of a symbol?
t.column "search_vectors", "tsvector"
If that doesn't work then you might need to drop down to database-specific SQL:
def self.up execute "--Put your PostgreSQL specific SQL statements here"end