Increase virtualbox memory, Resolve #1442

- Postgres needed more memory to run. All postgres tests fails with 2048MB.

deployment/vagrant-common/core.rb

@@ -95,7 +95,7 @@ def provider_virtualbox(config, role, ip_address='172.16.0.16')
       vb.gui = true
     end
 
-    vb.memory = ENV.fetch('TFB_VB_MEM', 2048)
+    vb.memory = ENV.fetch('TFB_VB_MEM', 3022)
     vb.cpus = ENV.fetch('TFB_VB_CPU', 2)
 
     # mount_options addresses issue mitchellh/vagrant#4997