Added test command to end of Dockerfile.meteor

Dockerfile.meteor

@@ -12,4 +12,5 @@ RUN cd && \
     wget -q "https://static-meteor.netdna-ssl.com/packages-bootstrap/${METEOR_VERSION}/meteor-bootstrap-os.linux.x86_64.tar.gz" -O meteor-bootstrap.tar.gz && \
     # The package only contains an ".meteor" directory that ends up in "/root/.meteor"
     tar -xzf meteor-bootstrap.tar.gz && \
-    rm meteor-bootstrap.tar.gz
+    rm meteor-bootstrap.tar.gz && \
+    ~/.meteor/meteor --version