elixir - Follow back functionality -

i have twitter application users can follow each other through connection model. in table lists people follow @user i'd implement link follow back. can link or have forms , display buttons? how setup changesets these forms?

web/models/user.ex

defmodule myapp.user   use myapp.web, :model   use arc.ecto.model    schema "users"     field :last_name, :string      has_many :follower_connections, myapp.connection, foreign_key: :followee_id     has_many :followers, through: [:follower_connections, :follower] [...] 

web/models/connection.ex

defmodule myapp.connection   use myapp.web, :model    schema "connections"     belongs_to :follower, myapp.user     belongs_to :followee, myapp.user [...] 

web/controllers/user_controller.ex

[...] def show(conn, %{"id" => id})   user =      repo.get!(user, id)      |> repo.preload([:followers, :follower_connections])    conn   |> assign(:user, user)   |> render("show.html") end [...] 

web/templates/user/show.html.eex

[...] <table>   <tbody> <%= connection <- @user.follower_connections %>     <tr>       <td><%= link connection.follower.last_name %></td>       <td>         <%= link ???????? "follow back" %>       </td>     </tr> <% end %>   </tbody> </table> [...] 

the link ???????? part problem.

you can link action implementing follow this:

link "follow back", to: user_path(@conn, :follow_back, user_id, []) 

the header this:

def follow_back(conn, %{"id" => id}) 

in router:

get "/follow_back/:id", usercontroller, :follow_back 

this solution skips changesets @ all. if want custom validation on data there great post on using embedded_schema forms aren't directly persisted database: http://blog.plataformatec.com.br/2016/05/ectos-insert_all-and-schemaless-queries/

the docs on html link here: https://hexdocs.pm/phoenix_html/phoenix.html.link.html tutorial on routing: http://www.phoenixframework.org/docs/routing , tutorial on controllers: http://www.phoenixframework.org/docs/controllers