Reload config on change (#527)

* Reload config on change.
Added test case.

* added testing for adding the json with reloadOnChange = false

test/Ocelot.AcceptanceTests/ConfigurationReloadTests.cs

@@ -0,0 +1,68 @@
+using Ocelot.Configuration.File;
+using Ocelot.Configuration.Setter;
+using Ocelot.Middleware;
+using Shouldly;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using TestStack.BDDfy;
+using Xunit;
+
+namespace Ocelot.AcceptanceTests
+{
+    public class ConfigurationReloadTests : IDisposable
+    {
+        private FileConfiguration _initialConfig;
+        private FileConfiguration _anotherConfig;
+        private Steps _steps;
+
+        public ConfigurationReloadTests()
+        {
+            _steps = new Steps();
+
+            _initialConfig = new FileConfiguration
+            {
+                GlobalConfiguration = new FileGlobalConfiguration
+                {
+                    RequestIdKey = "initialKey"
+                }
+            };
+
+            _anotherConfig = new FileConfiguration
+            {
+                GlobalConfiguration = new FileGlobalConfiguration
+                {
+                    RequestIdKey = "someOtherKey"
+                }
+            };
+        }
+
+        [Fact]
+        public void should_reload_config_on_change()
+        {           
+            this.Given(x => _steps.GivenThereIsAConfiguration(_initialConfig))
+                .And(x => _steps.GivenOcelotIsRunningReloadingConfig(true))
+                .And(x => _steps.GivenThereIsAConfiguration(_anotherConfig))
+                .And(x => _steps.GivenIWait(2500))
+                .And(x => _steps.ThenConfigShouldBe(_anotherConfig))
+                .BDDfy();
+        }
+
+        [Fact]
+        public void should_not_reload_config_on_change()
+        {
+           
+            this.Given(x => _steps.GivenThereIsAConfiguration(_initialConfig))
+                .And(x => _steps.GivenOcelotIsRunningReloadingConfig(false))
+                .And(x => _steps.GivenThereIsAConfiguration(_anotherConfig))
+                .And(x => _steps.GivenIWait(2500))
+                .And(x => _steps.ThenConfigShouldBe(_initialConfig))
+                .BDDfy();
+        }
+
+        public void Dispose()
+        {
+            _steps.Dispose();
+        }
+    }
+}