title: Rails migration giving error
body: <p>I created a model called customer. The migrate file is as follows:-</p>
  
  <pre><code>class CreateCustomers &lt; ActiveRecord::Migration[5.0]
    def change
          create_table :customers , :primary_key =&gt; :customer_id , do |t|
            t.integer :customer_id
            t.string :first_name
            t.string :last_name
            t.string :address_1
            t.string :address_2
            t.string :city
            t.string :state
            t.bigint :postal_code
  
            t.timestamps
          end
    end
  end
  </code></pre>
  
  <p>Now when I run rails db:migrate, this is the error that I get:-</p>
  
  <pre><code>rails aborted!
  SyntaxError: /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:3: syntax error, unexpected keyword_do_block
  imary_key =&gt; :customer_id , do |t|
                                ^
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:4: syntax error, unexpected tSYMBEG, expecting keyword_end
            t.integer :customer_id
                       ^
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:16: syntax error, unexpected keyword_end, expecting end-of-input
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/rails:9:in `require'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/rails:9:in `&lt;top (required)&gt;'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/spring:15:in `&lt;top (required)&gt;'
  bin/rails:3:in `load'
  bin/rails:3:in `&lt;main&gt;'
  Tasks: TOP =&gt; db:migrate
  (See full trace by running task with --trace)
  </code></pre>
  
  <p>The schema.rb file has no sign of the customer table either. Can someone help?
  EDIT:
  After removing the comma after customer_id I'm getting these:-</p>
  
  <pre><code>== 20170428100848 CreateCustomers: migrating ==================================
  -- create_table(:customers, {:primary_key=&gt;:customer_id})
  rails aborted!
  StandardError: An error has occurred, this and all later migrations canceled:
  
  you can't redefine the primary key column 'customer_id'. To define a custom primary key, pass { id: false } to create_table.
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:4:in `block in change'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:3:in `change'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/rails:9:in `require'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/rails:9:in `&lt;top (required)&gt;'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/spring:15:in `&lt;top (required)&gt;'
  bin/rails:3:in `load'
  bin/rails:3:in `&lt;main&gt;'
  ArgumentError: you can't redefine the primary key column 'customer_id'. To define a custom primary key, pass { id: false } to create_table.
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:4:in `block in change'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/db/migrate/20170428100848_create_customers.rb:3:in `change'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/rails:9:in `require'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/rails:9:in `&lt;top (required)&gt;'
  /home/gauri/Academics/CS/Ruby on Rails/ScholarShip/ScholarShip/bin/spring:15:in `&lt;top (required)&gt;'
  bin/rails:3:in `load'
  bin/rails:3:in `&lt;main&gt;'
  Tasks: TOP =&gt; db:migrate
  (See full trace by running task with --trace)
  </code></pre>