groovy/modules/grails/tomcat.xml

<project name="My Application" default="compile" basedir=".">

  <!-- Configure the directory into which the web application is built -->
  <property name="build"    value="PATH_TO_DIR_THAT_CONTAINS_WAR"/>     <!-- OVERRIDE FROM OUTSIDE -->

  <!-- Configure the context path for this application -->
  <property name="path"     value="/grails-app"/>

  <!-- Configure properties to access the Manager application -->
  <property name="url"      value="http://localhost:8080/manager"/>
  <property name="username" value="NO_USER_NAME"/>                      <!-- OVERRIDE FROM OUTSIDE -->
  <property name="password" value="NO_PASSWORD"/>                       <!-- OVERRIDE FROM OUTSIDE -->

  <!-- Configure the custom Ant tasks for the Manager application -->
  <taskdef name="deploy"    classname="org.apache.catalina.ant.DeployTask"/>
  <taskdef name="list"      classname="org.apache.catalina.ant.ListTask"/>
  <taskdef name="reload"    classname="org.apache.catalina.ant.ReloadTask"/>
  <taskdef name="resources" classname="org.apache.catalina.ant.ResourcesTask"/>
  <taskdef name="roles"     classname="org.apache.catalina.ant.RolesTask"/>
  <taskdef name="start"     classname="org.apache.catalina.ant.StartTask"/>
  <taskdef name="stop"      classname="org.apache.catalina.ant.StopTask"/>
  <taskdef name="undeploy"  classname="org.apache.catalina.ant.UndeployTask"/>

  <target name="deploy" description="Install web application"  >
    <deploy url="${url}" username="${username}" password="${password}"
            path="${path}" war="${build}${path}.war"/>
  </target>

  <target name="reload" description="Reload web application">
      <reload  url="${url}" username="${username}" password="${password}"
            path="${path}"/>
  </target>

  <target name="undeploy" description="Remove web application">
    <undeploy url="${url}" username="${username}" password="${password}"
            path="${path}"/>
  </target>

</project>