use atoms for role changeset

lib/cannery/accounts.ex

@@ -112,7 +112,7 @@ defmodule Cannery.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/cannery/accounts/user.ex

@@ -48,7 +48,7 @@ defmodule Cannery.Accounts.User do
   @type new_user :: %User{}
   @type id :: UUID.t()
   @type changeset :: Changeset.t(t() | new_user())
-  @type role :: :admin | :user | String.t()
+  @type role :: :admin | :user
 
   @doc """
   A user changeset for registration.
@@ -81,7 +81,7 @@ defmodule Cannery.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

@@ -43,7 +43,7 @@ defmodule Cannery.Fixtures do
     })
     |> Accounts.register_user()
     |> unwrap_ok_tuple()
-    |> User.role_changeset("admin")
+    |> User.role_changeset(:admin)
     |> Repo.update!()
   end