I looked at https://github.com/MinecraftForge/ForgeGradle/issues/46, and found out to add this to the bottom of the build.gradle:
reobf { deobfFile = new net.minecraftforge.gradle.delayed.DelayedFile(project, "build/tmp/deobfuscateJar/deobfed.jar") }
In the 1.7.2 forge gradle thingy, in eclipse, it says all the methods for setting item names and textures are working. However, when I run MC, any method from forge crashes with the exception thats something like: "java.lang.NoSuchMethodError". Is there something I missed?