Fixed generated Heroku setup script

When setting up each Ember application, looping through and installing
each application's dependencies, the generated `bin/heroku_install`
script should return to the current directory at the end of each
iteration.

Author: jeanbono

CHANGELOG.md

@@ -1,6 +1,9 @@
 master
 ------
 
+* Fix bug with generated `bin/heroku_install` script iterating through multiple
+  Ember application's directories.
+
 0.7.0
 -----
 

lib/generators/ember/heroku/templates/bin_heroku_install.erb

@@ -7,5 +7,6 @@ bower="$(pwd)/node_modules/.bin/bower"
 for app in <%= app_paths.map { |app_path| %{"#{app_path}"} }.join(" ") -%>; do
   cd $app &&
     npm install &&
-    $bower install
+    $bower install &&
+    cd -
 done