Delete postgres.js

remove placeholder file. postgres will not be used directly. More info:
 in gatewayd there are javascript models to interact with the database tables. These models are based on sequelize: http://sequelizejs.com/
[00:25:35] zeiler.steven: The various database models include:
[00:25:44] zeiler.steven: gatewayd.data.models.rippleTransactions
[00:25:52] zeiler.steven: gatewayd.data.models.rippleAddresses
[00:25:59] zeiler.steven: gatewayd.data.models.externalTransactions
[00:26:05] zeiler.steven: gatewayd.data.models.externalAccounts
[00:26:14] zeiler.steven: gatewayd.data.models.users
[00:26:29] zeiler.steven: gatewayd.data.models.kycData
[00:26:35] zeiler.steven: gatewayd.data.models.policies
[00:26:41] zeiler.steven: gatewayd.data.models.gatewayTransactions
[00:27:20] zeiler.steven: you can access these objects in javascript by doing "var gatewayd = require('/path/to/gatewayd')"
[00:28:37] zeiler.steven: for this plugin you will probably only need to use three database tables / models:
[00:28:49] zeiler.steven: externalAccounts, policies, and externalTransaction

*note: open an issue with this information as guidance