Add roles for users.

test/decentralised_book_index/accounts/role_test.exs

@@ -0,0 +1,31 @@
+defmodule DecentralisedBookIndex.Accounts.RoleTest do
+  use ExUnit.Case, async: true
+
+  alias DecentralisedBookIndex.Accounts.Role
+
+  @user :user
+  @moderator :moderator
+  @admin :admin
+
+  describe "can_moderate?" do
+    test "user can't moderate" do
+      refute Role.can_moderate?(@user)
+    end
+
+    test "moderator and admin can moderate" do
+      assert Role.can_moderate?(@moderator)
+      assert Role.can_moderate?(@admin)
+    end
+  end
+
+  describe "can_administrate?" do
+    test "user and moderator can't administrate" do
+      refute Role.can_administrate?(@user)
+      refute Role.can_administrate?(@moderator)
+    end
+
+    test "admin can administrate" do
+      assert Role.can_administrate?(@admin)
+    end
+  end
+end