Excludes demo classes in plugin jar

Closes gh-34

Author: rainboyan

build.gradle

@@ -99,6 +99,13 @@ task docs(type:Copy, group: 'documentation')  {
     into "$buildDir/docs"
 }
 
+jar {
+    enabled = true
+    archiveClassifier.set('plugin')
+    includeEmptyDirs = false
+    exclude 'testapp/*.class', 'databasemigration/*.class'
+}
+
 publishing {
     publications {
         maven(MavenPublication) {

src/main/groovy/org/grails/plugins/databasemigration/DatabaseMigrationGrailsPlugin.groovy

@@ -31,7 +31,8 @@ class DatabaseMigrationGrailsPlugin extends Plugin {
 
     def grailsVersion = "2023.0.0 > *"
     def pluginExcludes = [
-            "**/testapp/**",
+            'testapp/**',
+            'databasemigration/**',
             "grails-app/views/error.gsp"
     ]