inject message digest, move to configuration

service/src/main/java/com/telephoners/krakyournet/ctf/modules/ApplicationModule.java

 package com.telephoners.krakyournet.ctf.modules;
 
 import com.google.inject.AbstractModule;
+import com.google.inject.name.Names;
 import com.mongodb.MongoClient;
 import com.telephoners.krakyournet.ctf.core.ApplicationConfiguration;
 import org.mongodb.morphia.Datastore;
 import org.mongodb.morphia.Morphia;
 
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
 public class ApplicationModule extends AbstractModule
 {
 
@@ -28,5 +32,11 @@ public class ApplicationModule extends AbstractModule
                 new MongoClient(applicationConfiguration.getDbHost(), applicationConfiguration.getDbPort()), applicationConfiguration.getDbName());
         datastore.ensureIndexes();
         bind(Datastore.class).toInstance(datastore);
+        try {
+            bind(MessageDigest.class).annotatedWith(Names.named("messageDigest"))
+                    .toInstance(MessageDigest.getInstance(applicationConfiguration.getFlagHashMethod()));
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        }
     }
 }

service/src/main/java/com/telephoners/krakyournet/ctf/repositories/UsersRepository.java

@@ -2,14 +2,13 @@ package com.telephoners.krakyournet.ctf.repositories;
 
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
+import com.google.inject.name.Named;
 import com.telephoners.krakyournet.ctf.beans.User;
 import io.dropwizard.auth.basic.BasicCredentials;
 import org.apache.commons.codec.binary.Hex;
 import org.mongodb.morphia.Datastore;
 
 import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
-import java.util.List;
 
 @Singleton
 public class UsersRepository extends Repository<User>
@@ -17,14 +16,10 @@ public class UsersRepository extends Repository<User>
     private MessageDigest messageDigest;
 
     @Inject
-    public UsersRepository(Datastore datastore)
+    public UsersRepository(Datastore datastore, final @Named("messageDigest") MessageDigest messageDigest)
     {
         super(datastore);
-        try {
-            messageDigest = MessageDigest.getInstance("MD5"); //todo
-        } catch (NoSuchAlgorithmException e) {
-            e.printStackTrace();
-        }
+        this.messageDigest = messageDigest;
     }
 
     public User getUserByName(String username)