title: Insert many to many in Codeigniter with join
body: <p>I'm using Codeiginter to implement small project, I'm stuck with many to many idea.</p>
  
  <p>The problem is: If I have these entities</p>
  
  <hr>
  
  <p><strong>users</strong>(u_id,name)</p>
  
  <p><strong>cars</strong>(c_id,model)</p>
  
  <p><strong>users_cars</strong>(uc_id,u_id,c_id)</p>
  
  <hr>
  
  <p>And the user number 1 choose 3 cars model using checkbox, for example (1,2,3) model1 model2 model3.</p>
  
  <p>How can I implement this in Codeigniter? the (users_cars) entity should be (1,1,1)(2,1,2)(3,1,3).</p>