added database driven system configurations with admin screen (#647)

src/Entity/Configuration.php

@@ -0,0 +1,99 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Entity;
+
+use Doctrine\ORM\Mapping as ORM;
+use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
+use Symfony\Component\Validator\Constraints as Assert;
+
+/**
+ * @ORM\Entity(repositoryClass="App\Repository\ConfigurationRepository")
+ * @ORM\Table(
+ *      name="configuration",
+ *      uniqueConstraints={
+ *          @ORM\UniqueConstraint(columns={"name"})
+ *      }
+ * )
+ * @UniqueEntity("name")
+ */
+class Configuration
+{
+    /**
+     * @var int
+     *
+     * @ORM\Id
+     * @ORM\GeneratedValue
+     * @ORM\Column(name="id", type="integer")
+     */
+    private $id;
+
+    /**
+     * @var string
+     *
+     * @ORM\Column(name="name", type="string", length=100, nullable=false)
+     * @Assert\Length(min=2, max=100)
+     */
+    private $name;
+
+    /**
+     * @var string
+     *
+     * @ORM\Column(name="value", type="string", length=255, nullable=true)
+     */
+    private $value;
+
+    /**
+     * @return int
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * @return string
+     */
+    public function getName(): ?string
+    {
+        return $this->name;
+    }
+
+    /**
+     * @param string $name
+     * @return Configuration
+     */
+    public function setName(string $name): Configuration
+    {
+        $this->name = $name;
+
+        return $this;
+    }
+
+    /**
+     * Given $value will not be serialized before its stored, so it should be a scalar type.
+     *
+     * @param mixed $value
+     * @return Configuration
+     */
+    public function setValue($value): Configuration
+    {
+        $this->value = $value;
+
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    public function getValue(): ?string
+    {
+        return $this->value;
+    }
+}