Bump to GitBucket 4.15

Author: takezoe

Diff for: build.sbt

@@ -1,6 +1,6 @@
 val Organization = "io.github.gitbucket"
 val ProjectName = "gitbucket-gist-plugin"
-val ProjectVersion = "4.9.1"
+val ProjectVersion = "4.9.2"
 
 lazy val root = (project in file(".")).enablePlugins(SbtTwirl)
 
@@ -10,7 +10,7 @@ version := ProjectVersion
 scalaVersion := "2.12.2"
 
 libraryDependencies ++= Seq(
-  "io.github.gitbucket" %% "gitbucket"          % "4.14.1" % "provided",
+  "io.github.gitbucket" %% "gitbucket"          % "4.15.0" % "provided",
   "com.typesafe.play"   %% "twirl-compiler"     % "1.3.0"  % "provided",
   "javax.servlet"        % "javax.servlet-api"  % "3.1.0"  % "provided"
 )

Diff for: src/main/scala/Plugin.scala

@@ -31,7 +31,8 @@ class Plugin extends gitbucket.core.plugin.Plugin {
     new Version("4.7.0"),
     new Version("4.8.0"),
     new Version("4.9.0"),
-    new Version("4.9.1")
+    new Version("4.9.1"),
+    new Version("4.9.2")
   )
 
   override def initialize(registry: PluginRegistry, context: ServletContext, settings: SystemSettings): Unit = {