Add online beatmap "explicit content" property

osu.Game/Beatmaps/BeatmapSetOnlineInfo.cs

@@ -31,6 +31,11 @@ public class BeatmapSetOnlineInfo
         /// </summary>
         public BeatmapSetOnlineStatus Status { get; set; }
 
+        /// <summary>
+        /// Whether or not this beatmap set has explicit content.
+        /// </summary>
+        public bool HasExplicitContent { get; set; }
+
         /// <summary>
         /// Whether or not this beatmap set has a background video.
         /// </summary>

osu.Game/Online/API/Requests/Responses/APIBeatmapSet.cs

@@ -42,6 +42,9 @@ public int? OnlineBeatmapSetID
         [JsonProperty(@"bpm")]
         private double bpm { get; set; }
 
+        [JsonProperty(@"nsfw")]
+        private bool hasExplicitContent { get; set; }
+
         [JsonProperty(@"video")]
         private bool hasVideo { get; set; }
 
@@ -94,6 +97,7 @@ public BeatmapSetInfo ToBeatmapSet(RulesetStore rulesets)
                     FavouriteCount = favouriteCount,
                     BPM = bpm,
                     Status = Status,
+                    HasExplicitContent = hasExplicitContent,
                     HasVideo = hasVideo,
                     HasStoryboard = hasStoryboard,
                     Submitted = submitted,