override mongoid.yml defaults from env

config/mongoid.yml

@@ -17,9 +17,9 @@ common: &default_session
     skip_version_check: true
     safe: true
     consistency: strong
-    max_retries: 1
-    retry_interval: 0
-    timeout: 0.5
+    max_retries: <%= ENV['MONGOID_MAX_RETRIES'] || 1 %>
+    retry_interval: <%= ENV['MONGOID_RETRY_INTERVAL'] || 0 %>
+    timeout: <%= ENV['MONGOID_TIMEOUT'] || 0.5 %>
 
 production:
   sessions: