Add basic PGSQL connection

source/db/pgsql.d

@@ -0,0 +1,27 @@
+module db.pgsql;
+
+import db.db;
+
+import ddbc.core;
+import ddbc.common;
+
+class PostgresDB : DB {
+  shared this(Args...)(auto ref Args args) {
+    super(args);
+  }
+
+  protected override DataSource getDataSource() {
+    import ddbc.drivers.pgsqlddbc;
+
+    Driver driver = new PGSQLDriver();
+    string url;
+    string[string] params;
+
+    with (this.m_settings) {
+      url = PGSQLDriver.generateUrl(host, port, dbname);
+      params = PGSQLDriver.setUserAndPassword(username, password);
+    }
+
+    return new ConnectionPoolDataSourceImpl(driver, url, params);
+  }
+}