Ensure that the custom map is not null.

Author: jkodumal

src/main/java/com/launchdarkly/client/LDUser.java

@@ -55,6 +55,7 @@ public LDUser(Builder builder) {
    */
   public LDUser(String key) {
     this.key = key;
+    this.custom = new HashMap<String, JsonElement>();
   }
 
   String getKey() {

src/test/java/com/launchdarkly/client/FeatureRepTest.java

@@ -89,4 +89,13 @@ public void testDisabledFlagAlwaysOff() {
     assertEquals(null, b);
   }
 
+  @Test
+  public void testFlagWithCustomAttributeWorksWithLDUserDefaultCtor() {
+    LDUser user = new LDUser("randomUser@test.com");
+
+    Boolean b = simpleFlag.evaluate(user);
+
+    assertNotNull(b);
+  }
+
 }

src/test/java/com/launchdarkly/client/LDUserTest.java

@@ -65,4 +65,5 @@ public void testLDUserJsonSerializationContainsCountryAsTwoDigitCode() {
 
     assert(deserialized.getCountry().equals(LDCountryCode.US));
   }
+
 }