Updated documentation

* added RVM option for single-user install
* clarified Web Server options
* bluepill sample config: create socket directory if it doesn't exist
* add multisite.yml.production-sample
* rename production.sample.rb (OCD)
* make two database.yml samples (one for dev, one for prod)
* fixed travis build (database.yml.sample renamed)
* fix other references to database.yml.sample
* clean up 'rvm requirements' instructions as per @mpapis

config/database.yml.production-sample

@@ -0,0 +1,23 @@
+production:
+  adapter: postgresql
+  database: discourse_prod
+  # username: discourse_prod	# if using username/password auth
+  # password: itisagooddaytovi	# if using username/password auth
+  # host: dbhost		# if not localhost
+  pool: 5 	# size of DB connection pool *per process*
+  timeout: 5000
+  # db_id: 0	# database ID if hosting multiple sites
+  host_names:
+    - production.localhost # Update this to be the domain of your production site
+
+test:
+  adapter: postgresql
+  database: discourse_test
+  # username: discourse_test
+  # password: 123123123123
+  min_messages: warning
+  host: localhost
+  pool: 5
+  timeout: 5000
+  host_names:
+    - test.localhost