Extend all test tasks to run against every configured test db (WIP)

config/database.yml.dist

@@ -42,9 +42,24 @@ production:
 #  <<: *default
 #  database: fixinme_dev
 
-# Warning: The database defined as "test" will be erased and
-# re-generated from your development database when you run "rake".
-# Do not set this db to the same as development or production.
+# Warning: Test databases will be erased and re-generated from your development
+# database when you run "rake". Do not set these dbs to the same as development
+# or production.
+#
+# Multiple test databases can be provided. When more than one test db is
+# present, every test task (test, test:models, test:system, etc.) automatically
+# runs against all of them.
+#
+# In additional test databases only "adapter", "database", "host", "port" and
+# "socket" settings are used. All settings default to values specified in
+# "test" - which is required in all test setups.
 #test:
 #  <<: *default
 #  database: fixinme_test
+#
+#test_sqlite3:
+#  adapter: sqlite3
+#  database: db/fixinme_test.sqlite3
+#
+#test_postgresql:
+#  adapter: postgresql