Fix example by adding Gemfile.lock

Fixes #10
Fixes #12

Author: elia

.gitignore

@@ -2,7 +2,7 @@
 *.gem
 .yardoc
 .bundle
-Gemfile.lock
+/Gemfile.lock
 build/
 /.github_access_token
 /tmp

example/Gemfile.lock

@@ -0,0 +1,38 @@
+GIT
+  remote: git://github.com/opal/opal.git
+  revision: d77bd3ce19e101988578cdb6314d659491a77844
+  specs:
+    opal (0.11.99.dev)
+      ast (>= 2.3.0)
+      parser (= 2.5.1.0)
+
+PATH
+  remote: ..
+  specs:
+    opal-sprockets (0.4.2.pre.1.0.11.0.3.1)
+      opal (~> 0.11.0)
+      sprockets (~> 3.1)
+      tilt (>= 1.4)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.0)
+    concurrent-ruby (1.0.5)
+    parser (2.5.1.0)
+      ast (~> 2.4.0)
+    rack (2.0.5)
+    sprockets (3.7.2)
+      concurrent-ruby (~> 1.0)
+      rack (> 1, < 3)
+    tilt (2.0.8)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  opal!
+  opal-sprockets!
+
+BUNDLED WITH
+   1.16.4