Merge pull request #31 from sharelatex/csh-issue-1309-node-6.15.1

Bump node version to 6.15.1

services/real-time/.nvmrc

@@ -1 +1 @@
-6.9.5
+6.15.1

services/real-time/Jenkinsfile

@@ -15,7 +15,7 @@ pipeline {
     stage('Install') {
       agent {
         docker {
-          image 'node:6.9.5'
+          image 'node:6.15.1'
           args "-v /var/lib/jenkins/.npm:/tmp/.npm -e HOME=/tmp"
           reuseNode true
         }
@@ -33,7 +33,7 @@ pipeline {
     stage('Compile and Test') {
       agent {
         docker {
-          image 'node:6.9.5'
+          image 'node:6.15.1'
           args "-v /var/lib/jenkins/.npm:/tmp/.npm -e HOME=/tmp"
           reuseNode true
         }