add script to init mongodb for testing

tests/init_mongo.js

@@ -0,0 +1,9 @@
+# run this script with $ mongo < init_mongo.js
+
+use pwmantest
+
+db.createUser({user: "tester", pwd: "12345678",
+              roles: [{role: "dbAdmin", db: "pwmantest"},
+                      {role: "readWrite", db: "pwmantest"},]
+              })
+