📝 Add documentation about settings and env vars (#1118)

* Add doc and example for env var config

* Syntax highlight for .env file

* Add test for configuration docs

* 📝 Update settings docs, add more examples

* ✅ Add tests for settings

* 🚚 Rename "Application Configuration" to "Metadata and Docs URLs"

to disambiguate between that and settings

* 🔥 Remove replaced example file

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

tests/test_tutorial/test_metadata/test_tutorial001.py

@@ -0,0 +1,40 @@
+from fastapi.testclient import TestClient
+
+from metadata.tutorial001 import app
+
+client = TestClient(app)
+
+openapi_schema = {
+    "openapi": "3.0.2",
+    "info": {
+        "title": "My Super Project",
+        "version": "2.5.0",
+        "description": "This is a very fancy project, with auto docs for the API and everything",
+    },
+    "paths": {
+        "/items/": {
+            "get": {
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {"application/json": {"schema": {}}},
+                    }
+                },
+                "summary": "Read Items",
+                "operationId": "read_items_items__get",
+            }
+        }
+    },
+}
+
+
+def test_openapi_schema():
+    response = client.get("/openapi.json")
+    assert response.status_code == 200
+    assert response.json() == openapi_schema
+
+
+def test_items():
+    response = client.get("/items/")
+    assert response.status_code == 200
+    assert response.json() == [{"name": "Foo"}]