revise intoruction part

Author: skyhit

src/main/java/com/appirio/service/challengefeeder/manager/ChallengeDetailFeederManager.java

@@ -143,16 +143,19 @@ public void pushChallengeFeeder(ChallengeFeederParam param) throws SupplyExcepti
                     requirement = challenge.getStudioDetailRequirements();
                 }
 
-                String introduction = challenge.getIntroduction() != null ? "" : challenge.getIntroduction();
-                if (challenge.getRound1Introduction() != null) {
-                    if (challenge.getRound1Introduction() != null) {
-                        introduction += String.format(ROUND_HEADER_HTML, "1") + challenge.getRound1Introduction();
-                        introduction += "\n";
-                    }
-                }
-
-                if (challenge.getRound2Introduction() != null) {
-                    introduction += String.format(ROUND_HEADER_HTML, "2") + challenge.getRound2Introduction();
+                String introduction = challenge.getIntroduction() == null ? "" : challenge.getIntroduction();
+                String round1Introduction = challenge.getRound1Introduction() == null ? "" : challenge.getRound1Introduction();
+                String round2Introduction = challenge.getRound2Introduction() == null ? "" : challenge.getRound2Introduction();
+
+                if (round1Introduction != "" && round2Introduction != "") {
+                    // two rounds
+                    introduction += "\n" +
+                            String.format(ROUND_HEADER_HTML, "1") + round1Introduction + "\n"
+                            + String.format(ROUND_HEADER_HTML, "2") + round2Introduction;
+                } else if (round1Introduction != "") {
+                    introduction += "\n" + round1Introduction;
+                } else if (round2Introduction != "") {
+                    introduction += "\n" + round2Introduction;
                 }
 
                 challenge.setIntroduction(introduction);