Markdown Support (#45)

* Added Markdown response

* Added RenderMarkdownRequest

* Added MarkdownClient

* Fixed bool error for request

Author: dnagl

src/GitLabApiClient/MarkdownClient.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+using GitLabApiClient.Internal.Http;
+using GitLabApiClient.Models.Markdown.Request;
+using GitLabApiClient.Models.Markdown.Response;
+
+namespace GitLabApiClient
+{
+    /// <summary>
+    /// Used to render a markdown document.
+    /// </summary>
+    public sealed class MarkdownClient
+    {
+        private readonly GitLabHttpFacade _httpFacade;
+
+        internal MarkdownClient(GitLabHttpFacade httpFacade) => 
+            _httpFacade = httpFacade;
+
+        public async Task<Markdown> RenderAsync(RenderMarkdownRequest request) =>
+            await _httpFacade.Post<Markdown>($"api/v4/markdown", request);
+    }
+}

src/GitLabApiClient/Models/Markdown/Request/RenderMarkdownRequest.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using GitLabApiClient.Internal.Utilities;
+using Newtonsoft.Json;
+
+namespace GitLabApiClient.Models.Markdown.Request
+{
+    /// <summary>
+    /// Used to render a markdown document
+    /// </summary>
+    public sealed class RenderMarkdownRequest
+    {
+        /// <summary>
+        /// The markdown text to render
+        /// </summary>
+        [JsonProperty("text")]
+        public string Text { get; set; }
+
+        /// <summary>
+        /// Render text using GitLab Flavored Markdown
+        /// </summary>
+        [JsonProperty("gfm")]
+        public bool? FlavoredMarkdown { get; set; } = false;
+
+        /// <summary>
+        /// Use as a context when creating references using GitLab Flavored Markdown. Authentication is required if a project is not public.
+        /// </summary>
+        [JsonProperty("project")]
+        public string Project { get; set; }
+
+        public RenderMarkdownRequest(string text)
+        {
+            Guard.NotEmpty(text, nameof(text));
+            Text = text;
+        }
+    }
+}

src/GitLabApiClient/Models/Markdown/Response/Markdown.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Newtonsoft.Json;
+
+namespace GitLabApiClient.Models.Markdown.Response
+{
+    public sealed class Markdown
+    {
+        [JsonProperty("html")]
+        public string Html { get; set; }
+    }
+}