Updated some more stuff

build.gradle

@@ -1,14 +1,15 @@
+import com.anthonycicchetti.financetracker.DependencyVersions
+
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-  ext.kotlin_version = '1.2.60'
   repositories {
     google()
     jcenter()
   }
   dependencies {
-    classpath 'com.android.tools.build:gradle:3.1.3'
-    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    classpath "com.android.tools.build:gradle:${DependencyVersions.Android.Gradle}"
+    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${DependencyVersions.Kotlin}"
 
     // NOTE: Do not place your application dependencies here; they belong
     // in the individual module build.gradle files

buildSrc/src/main/kotlin/DependencyVersions.kt

@@ -12,5 +12,6 @@ object DependencyVersions {
 
     object Android {
         const val SupportLibrary = "27.1.1"
+        const val Gradle = "3.1.3"
     }
 }