How to Add a new column to an existing table via db:migrate

Use this command at rails console rails generate migration add_fieldname_to_tablename fieldname:string

and

rake db:migrate to run this migration

You can also do

rake db:rollback

if you have not added any data to the tables.Then edit the migration file by adding the email column to it and then call

rake db:migrate

This will work if you have rails 3.1 onwards installed in your system.

Much simpler way of doing it is change let the change in migration file be as it is. use

$rake db:migrate:redo.

This will roll back the last migration and migrate it again.