Add config method

Signed-off-by: Rahul Rudragoudar <rr83019@gmail.com>

src/main/java/lc/captchas/FontFunCaptcha.java

@@ -16,6 +16,10 @@ public class FontFunCaptcha implements ChallengeProvider {
     return "FontFunCaptcha";
   }
 
+  public void configure(String config) {
+    // TODO: Add custom config
+  }
+
   private String getFontName(String path, String level) {
     File file = new File(path + level + "/");
     FilenameFilter txtFileFilter =

src/main/java/lc/captchas/GifCaptcha.java

@@ -48,6 +48,10 @@ public class GifCaptcha implements ChallengeProvider {
     return null;
   }
 
+  public void configure(String config) {
+    // TODO: Add custom config
+  }
+
   public Challenge returnChallenge() {
     String secret = HelperFunctions.randomString(6);
     return new Challenge(gifCaptcha(secret), "image/gif", secret.toLowerCase());

src/main/java/lc/captchas/ShadowTextCaptcha.java

@@ -20,6 +20,10 @@ public class ShadowTextCaptcha implements ChallengeProvider {
     return "ShadowTextCaptcha";
   }
 
+  public void configure(String config) {
+    // TODO: Add custom config
+  }
+
   public boolean checkAnswer(String secret, String answer) {
     return answer.toLowerCase().equals(secret);
   }

src/main/java/lc/captchas/interfaces/ChallengeProvider.java

@@ -7,5 +7,5 @@ public interface ChallengeProvider {
 
   public boolean checkAnswer(String secret, String answer);
 
-  // TODO: def configure(): Unit
+  public void configure(String config);
 }