add dockerfile and update readme

Author: robandpdx

Dockerfile

@@ -0,0 +1,8 @@
+FROM node:14-slim
+WORKDIR /usr/src/app
+COPY package.json package-lock.json ./
+RUN npm ci --production
+RUN npm cache clean --force
+ENV NODE_ENV="production"
+COPY . .
+CMD [ "npm", "start" ]

README.md

@@ -46,6 +46,26 @@ There are two options to debug locally.
 1. Copy .env-sample to .env and populate with values specific for your GitHub app. [See here for more details](https://probot.github.io/docs/configuration/).
 1. From the VSCode `RUN AND DEBUG` menu select `Launch Probot` and click the green arrow to start debugging.
 
+## Docker
+
+```sh
+# 1. Run npm install
+npm install
+
+# 2. Build container
+docker build -t my-probot-app .
+
+# 3. Srouce your .env file
+export $(cat .env | xargs)
+
+# 3. Start container
+docker run \
+    -e APP_ID=$APP_ID \
+    -e PRIVATE_KEY=$PRIVATE_KEY \
+    -e WEBHOOK_SECRET=$WEBHOOK_SECRET \
+    my-probot-app
+```
+
 ## License
 
 [ISC](LICENSE)