module ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

def change_column_comment(table_name, column_name, comment_or_changes) # :nodoc:

:nodoc:
Adds comment for given table column or drops it if +comment+ is a +nil+ 
def change_column_comment(table_name, column_name, comment_or_changes) # :nodoc:
  clear_cache!
  comment = extract_new_comment_value(comment_or_changes)
  execute "COMMENT ON COLUMN #{quote_table_name(table_name)}.#{quote_column_name(column_name)} IS #{quote(comment)}"
end