adding some signing related configs

app/build.gradle

@@ -2,6 +2,12 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 
+def keystorePropertiesFile = rootProject.file("keystore.properties")
+def keystoreProperties = new Properties()
+if (keystorePropertiesFile.exists()) {
+    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
+}
+
 android {
     compileSdkVersion 29
     buildToolsVersion "29.0.3"
@@ -12,11 +18,21 @@ android {
         targetSdkVersion 29
         versionCode 1
         versionName "5.0.0"
-        multiDexEnabled true
         setProperty("archivesBaseName", "voice-recorder")
         vectorDrawables.useSupportLibrary = true
     }
 
+    signingConfigs {
+        if (keystorePropertiesFile.exists()) {
+            release {
+                keyAlias keystoreProperties['keyAlias']
+                keyPassword keystoreProperties['keyPassword']
+                storeFile file(keystoreProperties['storeFile'])
+                storePassword keystoreProperties['storePassword']
+            }
+        }
+    }
+
     buildTypes {
         debug {
             applicationIdSuffix ".debug"
@@ -24,6 +40,9 @@ android {
         release {
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+            if (keystorePropertiesFile.exists()) {
+                signingConfig signingConfigs.release
+            }
         }
     }