Generator generates a migration without .rb, Rails doesn't recognize it

[rrshaban]

Well this one stumped me for a while. The migration created by rails g make_flaggable made the following migration file:
20150418035621_create_make_flaggable_tables
Somehow, it forgot the .rb. This was giving me the following errors when I tried to do anything:

ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR:  relation "flaggings" does not exist
LINE 5:                WHERE a.attrelid = '"flaggings"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"flaggings"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

Renaming the file with a .rb and then running rake db:migrate fixed this problem.