Error after run heroku run rake db:migrate

Error after run heroku run rake db:migrate

I already ran "heroku pg:reset DATABASE".However,I still got this error.



Running rake db:migrate attached to terminal... up, run.8257 ==
AddPasswordDigestToUsers: migrating
======================================= -- add_column(:users,
:password_digest, :string) rake aborted! An error has occurred, this and
all later migrations canceled:
PG::Error: ERROR: relation "users" does not exist : ALTER TABLE "users"
ADD COLUMN "password_digest" character varying(255)/app/ve
ndor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connection_adap
ters/postgresql/database_statements.rb:128:in exec'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/postgresql/database_statements.rb:128:inblock in execute'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract_adapter.rb:425:in block in log'
/app/vendor/bundle/ruby/1.9.1/gems/activesupport-4.0.0/lib/active_support/notifi
cations/instrumenter.rb:20:ininstrument'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract_adapter.rb:420:in log'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/postgresql/database_statements.rb:127:inexecute'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract/schema_statements.rb:360:in add_column'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/postgresql/schema_statements.rb:379:inadd_column'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:625:in block in method_missing'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:597:inblock in say_with_time'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:597:in say_with_time'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:617:inmethod_missing'
/app/db/migrate/20130822145844_add_password_digest_to_users.rb:3:in
change'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:571:inexec_migration'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:555:in block (2 levels) in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:554:inblock in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract/connection_pool.rb:294:in with_connection'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:553:inmigrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:709:in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:959:inblock in execute_migration_in_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:1005:in block in ddl_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract/database_statements.rb:202:inblock in transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract/database_statements.rb:210:in within_new_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/connecti
on_adapters/abstract/database_statements.rb:202:intransaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/transact
ions.rb:209:in transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:1005:inddl_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:958:in execute_migration_in_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:920:inblock in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:916:in each'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:916:inmigrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:764:in up'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/migratio
n.rb:742:inmigrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-4.0.0/lib/active_record/railties
/databases.rake:42:in `block (2 levels) in ' Tasks: TOP => db:migrate
(See full trace by running task with --trace)
Any suggestion?