title: Generate migration - create join table
body: <p>I have looked through many <code>SO</code> and <code>google</code> posts for generating migration of join table for <code>has many and belongs to many</code> association and nothing work.</p>
  
  <p>All of the solutions are generating a empty migration file.</p>
  
  <p>I am using <code>rails 3.2.13</code> and I have two tables: <code>security_users</code> and <code>assignments</code>. These are some of things I have try:</p>
  
  <pre><code>rails generate migration assignments_security_users
  
  rails generate migration create_assignments_security_users
  
  rails generate migration create_assignments_security_users_join_table
  
  rails g migration create_join_table :products, :categories (following the official documentation)
  
  rails generate migration security_users_assignments security_user:belongs_to assignments:belongs_to 
  </code></pre>
  
  <p>Can anyone tell how to create a join table migration between two tables?</p>