Allow configuration options for Postgres (#2873)

* Allow configuration options for Postgres

* Fix the use of incorrect options object.

* Refactor and test the postgres config parser.

* Remove unnecessary try/catch

* Remove unnecessary try/catch

* Add blank line at the end of the test file

* Rename file for consistency purposes

src/Adapters/Storage/Postgres/PostgresClient.js

@@ -0,0 +1,26 @@
+const pgp = require('pg-promise')();
+const parser = require('./PostgresConfigParser');
+
+export function createClient(uri, databaseOptions) {
+  let client;
+  let dbOptions = {};
+  databaseOptions = databaseOptions || {};
+
+  if (uri) {
+    dbOptions = parser.getDatabaseOptionsFromURI(uri);
+  }
+
+  for (const key in databaseOptions) {
+    dbOptions[key] = databaseOptions[key];
+  }
+
+  client = pgp(dbOptions);
+
+  if (dbOptions.pgOptions) {
+    for (const key in dbOptions.pgOptions) {
+      client.pg.defaults[key] = dbOptions.pgOptions[key];
+    }
+  }
+
+  return client;
+}