Failed to apply plugin [id 'myappid']

I am new to gradle. My android app is supposed to be built command-line build with gradle on an osx machine. After resolving many issues with proxy & connectivity, I am finally getting an error when my script tries to build:

  A problem occurred evaluating root project 'android-build'.
    > Failed to apply plugin [id 'com.mycompany.myappid']
    > Plugin with id 'com.mycompany.myappid' not found.

How can I fix this issue ? Appreciate any suggestions pls

My build.gradle looks like below:

buildscript {
    repositories {
        maven  {
            url "http://repo1.maven.org/maven2"
        }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.1.3'
    }
}

apply plugin: 'com.mycompany.myappid'

android {
    compileSdkVersion 23
    buildToolsVersion "21.1.2"

    def versionPropsFile = file('version.properties')

    if (versionPropsFile.canRead()) {
        def Properties versionProps = new Properties()

        versionProps.load(new FileInputStream(versionPropsFile))

        def code = versionProps['VERSION_CODE'].toInteger() + 1

        versionProps['VERSION_CODE']=code.toString()
        versionProps.store(versionPropsFile.newWriter(), null)

        defaultConfig {
            versionCode code
            versionName "1.1"
            minSdkVersion 14
            targetSdkVersion 18
        }
    }
    else {
        throw new GradleException("Could not read version.properties!")
    }
}

This should be com.android.application. This is a plugin, not your application ID.