added vscode devcontainer

.devcontainer/Dockerfile

@@ -0,0 +1,57 @@
+#-------------------------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See https://go.microsoft.com/fwlink/?linkid=2090316 for license information.
+#-------------------------------------------------------------------------------------------------------------
+
+FROM node:12
+
+# Avoid warnings by switching to noninteractive
+ENV DEBIAN_FRONTEND=noninteractive
+
+# The node image includes a non-root user with sudo access. Use the "remoteUser"
+# property in devcontainer.json to use it. On Linux, the container user's GID/UIDs
+# will be updated to match your local UID/GID (when using the dockerFile property).
+# See https://aka.ms/vscode-remote/containers/non-root-user for details.
+ARG USERNAME=node
+ARG USER_UID=1000
+ARG USER_GID=$USER_UID
+
+# Configure apt and install packages
+RUN apt-get update \
+    && apt-get -y install --no-install-recommends apt-utils dialog 2>&1 \ 
+    #
+    # Verify git and needed tools are installed
+    && apt-get -y install git iproute2 procps \
+    #
+    # Remove outdated yarn from /opt and install via package 
+    # so it can be easily updated via apt-get upgrade yarn
+    && rm -rf /opt/yarn-* \
+    && rm -f /usr/local/bin/yarn \
+    && rm -f /usr/local/bin/yarnpkg \
+    && apt-get install -y curl apt-transport-https lsb-release \
+    && curl -sS https://dl.yarnpkg.com/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/pubkey.gpg | apt-key add - 2>/dev/null \
+    && echo "deb https://dl.yarnpkg.com/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
+    && apt-get update \
+    && apt-get -y install --no-install-recommends yarn \
+    #
+    # Install eslint globally
+    && npm install -g eslint \
+    #
+    # [Optional] Update a non-root user to UID/GID if needed.
+    && if [ "$USER_GID" != "1000" ] || [ "$USER_UID" != "1000" ]; then \
+        groupmod --gid $USER_GID $USERNAME \
+        && usermod --uid $USER_UID --gid $USER_GID $USERNAME \
+        && chown -R $USER_UID:$USER_GID /home/$USERNAME; \
+    fi \
+    # [Optional] Add add sudo support for non-root user
+    && apt-get install -y sudo \
+    && echo node ALL=\(root\) NOPASSWD:ALL > /etc/sudoers.d/$USERNAME \
+    && chmod 0440 /etc/sudoers.d/$USERNAME \
+    #
+    # Clean up
+    && apt-get autoremove -y \
+    && apt-get clean -y \
+    && rm -rf /var/lib/apt/lists/*
+
+# Switch back to dialog for any ad-hoc use of apt-get
+ENV DEBIAN_FRONTEND=dialog

.devcontainer/devcontainer.json

@@ -0,0 +1,29 @@
+// For format details, see https://aka.ms/vscode-remote/devcontainer.json or the definition README at
+// https://github.com/microsoft/vscode-dev-containers/tree/master/containers/javascript-node-12
+{
+	"name": "Node.js 12",
+	"dockerFile": "Dockerfile",
+
+	// Use 'settings' to set *default* container specific settings.json values on container create. 
+	// You can edit these settings after create using File > Preferences > Settings > Remote.
+	"settings": { 
+		"terminal.integrated.shell.linux": "/bin/bash"
+	},
+
+	// Use 'appPort' to create a container with published ports. If the port isn't working, be sure
+	// your server accepts connections from all interfaces (0.0.0.0 or '*'), not just localhost.
+	// "appPort": [],
+
+	// Uncomment the next line to run commands after the container is created.
+	// "postCreateCommand": "yarn install",
+
+	// Uncomment the next line to have VS Code connect as an existing non-root user in the container. 
+	// On Linux, by default, the container user's UID/GID will be updated to match your local user. See
+	// https://aka.ms/vscode-remote/containers/non-root for details on adding a non-root user if none exist.
+	// "remoteUser": "node",
+
+	// Add the IDs of extensions you want installed when the container is created in the array below.
+	"extensions": [
+		"dbaeumer.vscode-eslint"
+	]
+}