Added config files for testing code in Docker

Author: SanichKotikov

.dockerignore

@@ -0,0 +1 @@
+**/node_modules

CONTRIBUTING.md

@@ -7,7 +7,7 @@ First fork and clone the repo:
 git clone [email protected]:your-username/JsBarcode.git
 ````
 
-Then run ``npm install`` to set everything up. Make sure you have all dependencies of [node-canvas](https://github.com/Automattic/node-canvas) installed before doing this.
+Then run ``npm install`` to set everything up. Make sure you have all dependencies of [node-canvas](https://github.com/Automattic/node-canvas) installed before doing this, or check **Using Docker** section.
 
 You are now ready to start doing your changes.
 
@@ -30,6 +30,10 @@ JsBarcode has tests on all barcode symbologies (and more). If you want to test y
 
 There are also visual tests located under ``test/browser/``.
 
+Using Docker
+----
+If you have installed [Docker](https://www.docker.com), you can avoid local installation of dependencies for [node-canvas](https://github.com/Automattic/node-canvas). For doing that, run ``npm install --ignore-scripts`` instead of ``npm install``. Then you can run tests by ``docker-compose up``
+
 Symbologies and The Core
 ----
 JsBarcode is divided up in two distinct parts. The barcode symbologies (EAN-13, CODE128, ITF, ...) and the core.

Dockerfile

@@ -0,0 +1,13 @@
+FROM node:8
+
+RUN apt-get update && apt-get install -qq libcairo2-dev libjpeg-dev libpango1.0-dev libgif-dev build-essential g++
+
+RUN mkdir -p /frontend
+WORKDIR /frontend
+COPY ./ ./
+
+RUN npm install
+
+CMD npm test
+
+EXPOSE 3000

docker-compose.yml

@@ -0,0 +1,10 @@
+version: '2'
+services:
+  jsbarcode:
+    build:
+      context: ./
+    volumes:
+      - ./src:/frontend/src
+      - ./test:/frontend/test
+    ports:
+      - 3000:3000