Adding a gradle build file.

Change-Id: Ie6a8310b5c6d18db756f944e2dd981836a434719
diff --git a/build.gradle b/build.gradle
new file mode 100644
index 0000000..25c1608
--- /dev/null
+++ b/build.gradle
@@ -0,0 +1,13 @@
+apply plugin: 'java'
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ['guava/src']
+        }
+    }
+}
+
+dependencies {
+    compile project(':external:jsr305')
+}