Added 'ReadMe' property to NuGetPackSettings.

src/Cake.Common.Tests/Properties/Resources.resx

@@ -1559,4 +1559,38 @@ EndGlobal</value>
 &lt;/Solution&gt;
 </value>
   </data>
+  <data name="Nuspec_ReadMe" xml:space="preserve">
+    <value>&lt;?xml version="1.0" encoding="utf-8"?&gt;
+&lt;package xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
+  &lt;metadata xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd"&gt;
+    &lt;id&gt;The ID&lt;/id&gt;
+    &lt;version&gt;The version&lt;/version&gt;
+    &lt;title&gt;The title&lt;/title&gt;
+    &lt;authors&gt;Author #1,Author #2&lt;/authors&gt;
+    &lt;owners&gt;Owner #1,Owner #2&lt;/owners&gt;
+    &lt;licenseUrl&gt;https://license.com&lt;/licenseUrl&gt;
+    &lt;projectUrl&gt;https://project.com&lt;/projectUrl&gt;
+    &lt;icon&gt;images\icon.png&lt;/icon&gt;
+    &lt;iconUrl&gt;https://icon.com&lt;/iconUrl&gt;
+    &lt;requireLicenseAcceptance&gt;true&lt;/requireLicenseAcceptance&gt;
+    &lt;developmentDependency&gt;true&lt;/developmentDependency&gt;
+    &lt;description&gt;The description&lt;/description&gt;
+    &lt;summary&gt;The summary&lt;/summary&gt;
+    &lt;copyright&gt;The copyright&lt;/copyright&gt;
+    &lt;language&gt;en-us&lt;/language&gt;
+    &lt;tags&gt;Tag1 Tag2 Tag3&lt;/tags&gt;
+    &lt;serviceable&gt;true&lt;/serviceable&gt;
+    &lt;readme&gt;NuGet.org.md&lt;/readme&gt;
+    &lt;releaseNotes&gt;&lt;![CDATA[Line #1
+Line #2
+Line #3]]&gt;&lt;/releaseNotes&gt;
+  &lt;/metadata&gt;
+  &lt;files&gt;
+    &lt;file src="Cake.Core.dll" target="lib/net45" /&gt;
+    &lt;file src="Cake.Core.xml" target="lib/net45" /&gt;
+    &lt;file src="Cake.Core.pdb" target="lib/net45" /&gt;
+    &lt;file src="LICENSE" /&gt;
+  &lt;/files&gt;
+&lt;/package&gt;</value>
+  </data>
 </root>

src/Cake.Common.Tests/Unit/Tools/NuGet/Pack/NuGetPackerTests.cs

@@ -899,6 +899,42 @@ public void Should_Replace_Template_Tokens_In_Nuspec_With_Files_And_DependencyTa
                         Resources.Nuspec_Metadata_WithoutNamespaces_WithTargetFramworkDependencies.NormalizeLineEndings(),
                         result.NuspecContent.NormalizeLineEndings());
                 }
+
+                [Fact]
+                public void Should_Add_ReadMe_Element_To_Nuspec_If_Missing()
+                {
+                    // Given
+                    var fixture = new NuGetPackerWithNuSpecFixture();
+                    fixture.WithNuSpecXml(Resources.Nuspec_NoMetadataElement);
+
+                    fixture.Settings.Id = "The ID";
+                    fixture.Settings.Version = "The version";
+                    fixture.Settings.Title = "The title";
+                    fixture.Settings.Authors = new[] { "Author #1", "Author #2" };
+                    fixture.Settings.Owners = new[] { "Owner #1", "Owner #2" };
+                    fixture.Settings.Description = "The description";
+                    fixture.Settings.Summary = "The summary";
+                    fixture.Settings.LicenseUrl = new Uri("https://license.com");
+                    fixture.Settings.ProjectUrl = new Uri("https://project.com");
+                    fixture.Settings.Icon = @"images\icon.png";
+                    fixture.Settings.IconUrl = new Uri("https://icon.com");
+                    fixture.Settings.DevelopmentDependency = true;
+                    fixture.Settings.RequireLicenseAcceptance = true;
+                    fixture.Settings.Copyright = "The copyright";
+                    fixture.Settings.ReleaseNotes = new[] { "Line #1", "Line #2", "Line #3" };
+                    fixture.Settings.Tags = new[] { "Tag1", "Tag2", "Tag3" };
+                    fixture.Settings.Language = "en-us";
+                    fixture.Settings.Serviceable = true;
+                    fixture.Settings.ReadMe = "NuGet.org.md";
+
+                    // When
+                    var result = fixture.Run();
+
+                    // Then
+                    Assert.Equal(
+                        Resources.Nuspec_ReadMe.NormalizeLineEndings(),
+                        result.NuspecContent.NormalizeLineEndings());
+                }
             }
 
             public sealed class WithProjectFile

src/Cake.Common/Tools/NuGet/Pack/NuGetPackSettings.cs

@@ -272,5 +272,14 @@ public sealed class NuGetPackSettings : ToolSettings
         /// <c>true</c> if the output should be placed in the tool folder inside the NuGet package; otherwise <c>false</c>.
         /// </value>
         public bool OutputToToolFolder { get; set; }
+
+        /// <summary>
+        /// Gets or sets the path to the readme file in the package.
+        /// The file needs to be part of the package files.
+        /// </summary>
+        /// <value>
+        /// The path to a file included in the package, relative to the root of the package.
+        /// </value>
+        public FilePath ReadMe { get; set; }
     }
 }

src/Cake.Common/Tools/NuGet/Pack/NuspecTransformer.cs

@@ -54,7 +54,8 @@ private static IDictionary<string, Func<NuGetPackSettings, string>> CreateMappin
                 { "copyright", x => ToString(settings.Copyright) },
                 { "language", x => ToString(settings.Language) },
                 { "tags", x => ToSpaceSeparatedString(settings.Tags) },
-                { "serviceable", x => ToString(settings.Serviceable) }
+                { "serviceable", x => ToString(settings.Serviceable) },
+                { "readme", x => ToString(settings.ReadMe?.FullPath) }
             };
         }