Add devcontainer settings

.devcontainer/devcontainer.json

@@ -0,0 +1,18 @@
+{
+  "name": "dev-optuna-dashboard",
+  "dockerFile": "Dockerfile",
+  "forwardPorts": [9000],
+  "containerEnv": {},
+  "runArgs": ["--init"],
+  "postCreateCommand": "./.devcontainer/postCreateCommand.sh",
+  "customizations": {
+    "vscode": {
+      "settings": {
+        "editor.renderWhitespace": "all"
+      },
+      "extensions": [
+        "ms-python.python"
+      ]
+    }
+  }
+}