Add Drone CI

- Add drone test environment
- Add drone config
- apt phpunit
- Fix api.php
- Fix item.php
- Fix DBStructure
- Check if caching is possible during tests

bin/wait-for-connection

@@ -0,0 +1,40 @@
+#!/usr/bin/php
+
+<?php
+$timeout = 60;
+switch ($argc) {
+	case 4:
+		$timeout = (float)$argv[3];
+	case 3:
+		$host = $argv[1];
+		$port = (int)$argv[2];
+		break;
+	default:
+		fwrite(STDERR, 'Usage: '.$argv[0].' host port [timeout]'."\n");
+		exit(2);
+}
+if ($timeout < 0) {
+	fwrite(STDERR, 'Timeout must be greater than zero'."\n");
+	exit(2);
+}
+if ($port < 1) {
+	fwrite(STDERR, 'Port must be an integer greater than zero'."\n");
+	exit(2);
+}
+$socketTimeout = (float)ini_get('default_socket_timeout');
+if ($socketTimeout > $timeout) {
+	$socketTimeout = $timeout;
+}
+$stopTime = time() + $timeout;
+do {
+	$sock = @fsockopen($host, $port, $errno, $errstr, $socketTimeout);
+	if ($sock !== false) {
+		fclose($sock);
+		fwrite(STDOUT, "\n");
+		exit(0);
+	}
+	sleep(1);
+	fwrite(STDOUT, '.');
+} while (time() < $stopTime);
+fwrite(STDOUT, "\n");
+exit(1);