Solved Gralde can't find method compileOnly()

Hi I am having an issue. So, I am trying to setup an Eclipse Gradle project with the spigot-api 1.15.1, and it's telling me that compileOnly isn't a thing...

My gradle version is 5.6.1 and here is there error I am getting:

Code (Text):

Could not run phased build action using Gradle distribution 'https://services.gradle.org/distributions/gradle-5.6.1-bin.zip'.
Build file 'C:\Users\Pmatt\Documents\Plugins\TerrainControl2\build.gradle' line: 14
A problem occurred evaluating root project 'TerrainControl2'.
Could not find method compileOnly() for arguments [org.spigotmc:spigot-api:1.15.1-R0.1-SNAPSHOT] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

Here is the section creating the error. I have no idea what's wrong.

Code (Text):

dependencies {
    compileOnly 'org.spigotmc:spigot-api:1.15.1-R0.1-SNAPSHOT'
}

 

I decided to create a new gradle project in eclipse to see if that would work and it did. Odd.