Feat: add static analytic of code

build.gradle

@@ -2,6 +2,7 @@ plugins {
 	id 'java-library'
 	id 'application'
 	id 'com.github.johnrengelman.shadow' version '7.1.2'
+	id 'pmd'
 }
 
 sourceCompatibility = '1.11'
@@ -63,3 +64,9 @@ jar {
 		configurations.implementation.collect { it.isDirectory() ? it : zipTree(it) }
 	}
 }
+
+pmd {
+	ignoreFailures = false
+	ruleSetFiles = files("rulesets/java-sheepit.xml")
+	ruleSets = []
+}