Enabled proguard for both debug and release versions and fixed the gradle warnings related to proguard unsatisfied rules in a correct way without ignoring all possible warnings.

app/build.gradle

@@ -21,6 +21,9 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
         debug {
+            minifyEnabled true
+            shrinkResources true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
             resValue("string", "PORT_NUMBER", "8082")
         }
     }

app/proguard-rules.pro

@@ -20,5 +20,7 @@
 # hide the original source file name.
 #-renamesourcefileattribute SourceFile
 
-## TODO actually fix this
--ignorewarnings
+-dontwarn sun.misc.Unsafe
+-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
+-dontwarn org.bitcoinj.store**
+-dontwarn org.slf4j.**