add RelationType SQLAlchemy ORM model

Signed-off-by: Kevin Morris <kevr@0cost.org>

aurweb/models/relation_type.py

+from sqlalchemy.orm import mapper
+
+from aurweb.schema import RelationTypes
+
+
+class RelationType:
+    def __init__(self, Name: str = None):
+        self.Name = Name
+
+
+mapper(RelationType, RelationTypes)

test/test_relation_type.py

+import pytest
+
+from aurweb.db import create, delete, query
+from aurweb.models.relation_type import RelationType
+from aurweb.testing import setup_test_db
+
+
+@pytest.fixture(autouse=True)
+def setup():
+    setup_test_db()
+
+
+def test_relation_type_creation():
+    relation_type = create(RelationType, Name="test-relation")
+    assert bool(relation_type.ID)
+    assert relation_type.Name == "test-relation"
+
+    delete(RelationType, RelationType.ID == relation_type.ID)
+
+
+def test_relation_types():
+    conflicts = query(RelationType, RelationType.Name == "conflicts").first()
+    assert conflicts is not None
+    assert conflicts.Name == "conflicts"
+
+    provides = query(RelationType, RelationType.Name == "provides").first()
+    assert provides is not None
+    assert provides.Name == "provides"
+
+    replaces = query(RelationType, RelationType.Name == "replaces").first()
+    assert replaces is not None
+    assert replaces.Name == "replaces"