Try to fix Dockerfile.

Dockerfile

@@ -87,7 +87,9 @@ RUN \
     #tar xvzf node-${NODE_VERSION}-${ARCHITECTURE}.tar.gz && \
     #rm node-${NODE_VERSION}-${ARCHITECTURE}.tar.gz && \
     #mv node-${NODE_VERSION}-${ARCHITECTURE} /opt/nodejs && \
-    mv node /opt/nodejs && \
+    mkdir -p /opt/nodejs/bin &&
+    mv node /opt/nodejs/bin/ && \
+    mv npm /opt/nodejs/bin/ && \
     ln -s /opt/nodejs/bin/node /usr/bin/node && \
     ln -s /opt/nodejs/bin/npm /usr/bin/npm && \
     \

download-sandstorm-node.sh

@@ -27,6 +27,7 @@ SIGNING_KEY_ID=160D2D577518B58D94C9800B63F227499DA8CCBD
 
 TARBALL=sandstorm-$SANDSTORM_LAST_BUILD.tar.xz
 NODE_EXE=sandstorm-$SANDSTORM_LAST_BUILD/bin/node
+NPM_EXE=sandstorm-$SANDSTORM_LAST_BUILD/bin/npm
 
 echo "=== DOWNLOADING SANDSTORM GPG KEYS TO VERIFY SANDSTORM RELEASE ==="
 
@@ -60,7 +61,7 @@ fi
 
 echo "=== EXTRACTING NODE FROM SANDSTORM RELEASE TARBALL ==="
 # --strip 2 removes path of 2 subdirectories
-tar -xf $TARBALL $NODE_EXE --strip=2
+tar -xf $TARBALL $NODE_EXE $NPM_EXE --strip=2
 
 echo "=== REMOVING SANDSTORM RELEASE TARBALL AND SIGNATURE ==="
 rm $TARBALL $TARBALL.sig release-certificate.kentonv.si*