Add minimal documentation for Gradle

Author: mdesharnais

md/gradle.md

@@ -0,0 +1,59 @@
+# Gradle
+
+Jooby is being developed with Maven and it is currently the *official* build
+tool. Even though it is a long-term goal of the project to accommodate alternative
+tooling, it is not known when such support will materialized itself. In the
+meantime, some compromises have to be made to walk off the beaten path.
+
+The goal of this document is to document the current state of the art to
+duplicate a Maven development environment to Gradle.
+
+## A minimal `build.gradle`
+
+```
+/*
+ * We are writing a standalone application.
+ */
+apply plugin: 'application'
+
+/*
+ * Some classic project configuration.
+ */
+version = 0.1
+mainClassName = "my.package.Main"
+sourceCompatibility = 1.8
+
+/*
+ * Dependencies will be downloaded from the Maven repository.
+ */
+repositories {
+    mavenCentral()
+}
+
+/*
+ * A minimal project needs the framwork and a webserver.
+ */
+dependencies {
+  compile group: 'org.jooby', name: 'jooby', version: '0.16.0'
+  compile group: 'org.jooby', name: 'jooby-netty', version: '0.16.0'
+}
+
+/*
+ * We diverge from the default resources structure to adopt the Jooby standard.
+ */
+sourceSets.main.resources {
+    srcDirs = ["conf", "public"]
+}
+```
+
+## What works
+
+- **Compiling the application** can be done as usual with `gradle build`.
+
+- **Running the application** can be done as usual with `gradle run` but the
+  automatic reloading of resources or java classes does not work.
+
+
+## What does not work
+
+- **Everything else.**