To create a new users table with the columns name and salary, run the command:
rails generate migration CreateUsers name:string salary:decimal
This will generate the following migration:
class CreateUsers < ActiveRecord::Migration[5.0]
def change
create_table :users do |t|
t.string :name
t.decimal :salary
end
end
end
When the migration name is of the form CreateXXX followed by list of columns with data types, then a migration will be generated that creates the table XXX with the listed columns.