Add API for creating new users

tests/api/test_user.py

@@ -0,0 +1,15 @@
+import json
+
+import pytest
+
+
+@pytest.mark.usefixtures('db')
+def test_post(client):
+    data = {
+        'name'      : 'Blue Stahli',
+        'password'  : 'metamorphosis',
+        'username'  : 'BlueStahli',
+    }
+    response = client.post('/user/', data=json.dumps(data))
+    assert response.status_code == 204
+    assert response.headers['Location']