docs: Add sponsors page

(cherry picked from commit b40409141f)

docs/index.rst

@@ -118,6 +118,7 @@ About
     :maxdepth: 1
 
     authors
+    sponsors
     changelog
     versioning
 

docs/sponsors.rst

@@ -0,0 +1,38 @@
+.. _sponsors:
+
+********
+Sponsors
+********
+
+The Mopidy project would like to thank the following sponsors for supporting
+the project.
+
+
+Rackspace
+=========
+
+`Rackspace <http://www.rackspace.com/>`_ lets Mopidy use their hosting services
+for free. We use their services for the following sites:
+
+- Hosting of the APT package repository at https://apt.mopidy.com.
+
+- Hosting of the Discourse forum at https://discuss.mopidy.com.
+
+- Mailgun for sending emails from the Discourse forum.
+
+- Hosting of the Jenkins CI server at https://ci.mopidy.com.
+
+- Hosting of a Linux worker for https://ci.mopidy.com.
+
+- Hosting of a Windows worker for https://ci.mopidy.com.
+
+- CDN hosting at http://dl.mopidy.com, which is used to distribute Pi Musicbox
+  images.
+
+
+GlobalSign
+==========
+
+`GlobalSign <https://www.globalsign.com/>`_ provides Mopidy with a free
+wildcard SSL certificate for mopidy.com, which we use to secure access to all
+our web sites.