reenabled admin area; outfitted apps.lyric.models w. AbstractBaseUser instead of custom user class; many other fns & several models updated to accomodate, such as set_unusable_password() method to base user model; reset staging db to prepare for refreshed lyric migrations to accomodate for retrofitted pw field

src/functional_tests/test_admin.py

@@ -0,0 +1,28 @@
+from selenium.webdriver.common.by import By
+
+from .base import FunctionalTest
+from apps.lyric.models import User
+
+
+class AdminLoginTest(FunctionalTest):
+    def setUp(self):
+        super().setUp()
+        self.superuser = User.objects.create_superuser(
+            email="admin@example.com",
+            password="correct-password",
+        )
+
+    def test_can_access_admin(self):
+        self.browser.get(self.live_server_url + "/admin/")
+
+        self.wait_for(lambda: self.browser.find_element(By.ID, "id_username"))
+        self.browser.find_element(By.ID, "id_username").send_keys("admin@example.com")
+        self.browser.find_element(By.ID, "id_password").send_keys("correct-password")
+        self.browser.find_element(By.CSS_SELECTOR, "input[type=submit]").click()
+
+        body = self.wait_for(
+            lambda: self.browser.find_element(By.TAG_NAME, "body")
+        )
+        self.assertIn("Site administration", body.text)
+        self.assertIn("Users", body.text)
+        self.assertIn("Tokens", body.text)