okay first lets create 2 folders, one for gradle setup & one for your development environment
download forge src & extract the contents into the "gradle setup" folder you just created then create a new .bat file & edit the text inside so it says "gradlew.bat eclipse" save it then run the .bat you just created
next open up eclipse and change the location to the "development environment" folder you just created
after its all loaded click on "help" & eclipse market place, & search for "gradle intergration" & install (you will have to restart eclipse)
click on file & then import & click on gradle then gradle project
browse to your "grade setup" folder & then click build model
click on the project that pops up then click finish (it will take a few minutes to setup)
now your gradle files should all be setup
now go to "run configurations" & right click on "java application" & create a one called "start_server"
click on the search button & select "ServerLauncherWrapper" & click ok your server should launch successfully
now in "run configurations" again create another "java application" and just call it "start_client"
click on the search button & select "Launch" & click ok, next click on the arguments tab ...
in the Program arguments put the following text "--version 1.6 --tweakClass cpw.mods.fml.common.launcher.FMLTweaker"
in the VM arguments put the following text "-Xincgc -Xmx512M -Xms512M -Dfml.ignoreInvalidMinecraftCertificates=true" click apply
SUCCESS you should have forge gradle setup