also install GB deps in docker build, fix #2278

Dockerfile

@@ -11,12 +11,19 @@ WORKDIR /usr/src/app
 RUN npm install -g --production node-gyp && \
     npm cache clean --force
 
-# Install app dependencies
-COPY package.json /usr/src/app
+# Install Gekko dependencies
+COPY package.json .
 RUN npm install --production && \
     npm install --production redis@0.10.0 talib@1.0.2 tulind@0.8.7 pg && \
     npm cache clean --force
 
+# Install Gekko Broker dependencies
+WORKDIR exchange
+COPY exchange/package.json .
+RUN npm install --production && \
+    npm cache clean --force
+WORKDIR ../
+
 # Bundle app source
 COPY . /usr/src/app