use atoms for role changeset

lib/memex/accounts.ex

@@ -112,7 +112,7 @@ defmodule Memex.Accounts do
     |> Multi.one(:users_count, from(u in User, select: count(u.id), distinct: true))
     |> Multi.insert(:add_user, fn %{users_count: count} ->
       # if no registered users, make first user an admin
-      role = if count == 0, do: "admin", else: "user"
+      role = if count == 0, do: :admin, else: :user
 
       User.registration_changeset(attrs) |> User.role_changeset(role)
     end)

lib/memex/accounts/user.ex

@@ -50,7 +50,7 @@ defmodule Memex.Accounts.User do
   @type new_user :: %__MODULE__{}
   @type id :: UUID.t()
   @type changeset :: Changeset.t(t() | new_user())
-  @type role :: :user | :admin | String.t()
+  @type role :: :user | :admin
 
   @doc """
   A user changeset for registration.
@@ -84,7 +84,7 @@ defmodule Memex.Accounts.User do
   """
   @spec role_changeset(t() | new_user() | changeset(), role()) :: changeset()
   def role_changeset(user, role) do
-    user |> cast(%{"role" => role}, [:role])
+    user |> change(role: role)
   end
 
   @spec validate_email(changeset()) :: changeset()

test/support/fixtures.ex

@@ -29,7 +29,7 @@ defmodule Memex.Fixtures do
     })
     |> Accounts.register_user()
     |> unwrap_ok_tuple()
-    |> User.role_changeset("admin")
+    |> User.role_changeset(:admin)
     |> Repo.update!()
   end