chore: add dockerfile to build extension

.dockerignore

@@ -1 +1,2 @@
 node_modules/
+Dockerfile

Dockerfile

@@ -0,0 +1,13 @@
+FROM nikolaik/python-nodejs:python3.9-nodejs14 as build
+LABEL maintainer="ux@blockstack.com"
+
+COPY . .
+
+RUN apt-get update && \
+    apt-get install -y zip make && \
+    ./build-ext.sh
+
+FROM alpine:latest
+COPY --from=build extension.zip .
+
+CMD sleep 60

README.md

@@ -25,4 +25,16 @@ For development instructions of specific packages, see the `README` in each pack
 ## Building browser extensions
 
 1. From the root of this repository, in the command line, run `sh build-ext.sh`
-2. The extension will be packaged as `extension.zip` inside this folder.
+2. The extension will be packaged as `extension.zip` inside this folder.
+
+### Optional - Build browser extensions using Docker
+
+1. Build the docker image locally:
+    ```bash
+    docker build . -t ux
+    ```
+
+1. Copy the built extensions to your local machine:
+    ```bash
+    docker run -d --name ux ux && docker cp ux:extension.zip . && docker rm -f ux
+    ```