title: Ruby on Rails database: how to mention foreign key relation by changing app/model/table.rb file how to know they implemented
body: <p>I am new to RoR. I used "rails generate model ServiceConfigs" command to generate a table. 
  so may commands are as below
   rails generate model ServiceConfigs configs:string
   rake db:migrate 
  -- can see app/db/service_config.rb created. 
  Now edited service_config.rb file to add 2 columns and which has a foreign key relation to service table. So here is code </p>
  
  <pre><code>class ServiceConfigs &lt; ActiveRecord::Base
    belongs_to :service, :dependent =&gt; :destroy 
  
    validates_presence_of :configs
  end
  </code></pre>
  
  <p>Now when I login to underline database, and look at the table I don't see foreign key relation in table schema. Whats wrong/more I need to do?</p>
  
  <p>highly appreciate your time and help
  Krishna</p>