Merge pull request #361 from coralproject/yarn-docker

Yarn fixes for Docker

Dockerfile

@@ -1,7 +1,7 @@
 FROM node:7.6
 
-# Install yarn
-RUN npm install -g yarn
+# Add node-gyp for bcrypt build support
+RUN yarn global add node-gyp
 
 # Create app directory
 RUN mkdir -p /usr/src/app