Move installation to onCreateCommand

.devcontainer/devcontainer.json

@@ -13,7 +13,5 @@
 			}
 		}
   },
-  // "onCreateCommand": "sudo cp .devcontainer/welcome-message.txt /usr/local/etc/vscode-dev-containers/first-run-notice.txt",
-  "postCreateCommand": "sudo chmod +x .devcontainer/post-create-command.sh && .devcontainer/post-create-command.sh",
-  "waitFor": "postCreateCommand"
+  "onCreateCommand": "sudo chmod +x .devcontainer/on-create-command.sh && .devcontainer/on-create-command.sh"
 }

.devcontainer/on-create-command.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+set -e
+
+if ! git remote | grep -q "fork"; then
+    git remote add fork https://github.com/${GITHUB_USER}/flask
+fi
+
+python3 -m venv .venv
+. .venv/bin/activate
+pip install --upgrade pip setuptools
+pip install -r requirements/dev.txt && pip install -e .
+pre-commit install
+
+sudo cp .devcontainer/welcome-message.txt /usr/local/etc/vscode-dev-containers/first-run-notice.txt