[WIP][growth] Require Basic Authentication, when accessing `Growthforecast`.
[growthforecast] Require Basic Authentication, when accessing `Growthforecast`.

- Require Basic Authentication
- Add password file for Basic Authentication
- Add tests for this change
[growthforecast] Make sure that the `Basic Authentication` config should be applied by restarting the server.

```
diff --git a/site-cookbooks/growthforecast/recipes/growthforecast.rb b/site-cookbooks/growthforecast/recipes/growthforecast.rb
index 85cfe28..b97c532 100644
--- a/site-cookbooks/growthforecast/recipes/growthforecast.rb
+++ b/site-cookbooks/growthforecast/recipes/growthforecast.rb
@@ -64,7 +64,7 @@ template "/etc/nginx/sites-available/growth" do

   mode 0644

-  notifies :reload, "service[nginx]"
+  notifies :restart, "service[nginx]"
 end

 cookbook_file "/etc/nginx/.htpasswd_growth" do
@@ -73,7 +73,7 @@ cookbook_file "/etc/nginx/.htpasswd_growth" do

   mode    0644

-  notifies :reload, "service[nginx]"
+  notifies :restart, "service[nginx]"
 end

 link "/etc/nginx/sites-enabled/growthforecast" do
```
Merge pull request #163 from kazu634/growthforecast-basic-auth

[growthforecast] Require Basic Authentication, when accessing `Growthforecast`.