Adding diff_refs in MergeRequest #291 (#300)

src/main/java/org/gitlab4j/api/models/DiffRef.java

+package org.gitlab4j.api.models;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class DiffRef {
+    private String baseSha;
+    private String headSha;
+    private String startSha;
+
+    public DiffRef() {
+    }
+
+    public String getBaseSha() {
+        return baseSha;
+    }
+
+    public void setBaseSha(final String baseSha) {
+        this.baseSha = baseSha;
+    }
+
+    public String getHeadSha() {
+        return headSha;
+    }
+
+    public void setHeadSha(final String headSha) {
+        this.headSha = headSha;
+    }
+
+    public String getStartSha() {
+        return startSha;
+    }
+
+    public void setStartSha(final String startSha) {
+        this.startSha = startSha;
+    }
+}

src/main/java/org/gitlab4j/api/models/MergeRequest.java

 package org.gitlab4j.api.models;
 
-import java.util.Date;
-import java.util.List;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+import org.gitlab4j.api.utils.JacksonJson;
 
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlRootElement;
-
-import org.gitlab4j.api.utils.JacksonJson;
-
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+import java.util.Date;
+import java.util.List;
 
 @XmlRootElement
 @XmlAccessorType(XmlAccessType.FIELD)
@@ -47,6 +46,7 @@ public class MergeRequest {
     private Integer userNotesCount;
     private String webUrl;
     private Boolean workInProgress;
+    private DiffRef diffRefs;
 
     // The approval fields will only be available when listing approvals, approving  or unapproving a merge reuest.
     private Integer approvalsRequired;
@@ -370,6 +370,14 @@ public class MergeRequest {
         this.approvedBy = approvedBy;
     }
 
+    public DiffRef getDiffRefs() {
+        return diffRefs;
+    }
+
+    public void setDiffRefs(final DiffRef diffRefs) {
+        this.diffRefs = diffRefs;
+    }
+
     public static final boolean isValid(MergeRequest mergeRequest) {
         return (mergeRequest != null && mergeRequest.getId() != null);
     }

src/test/resources/org/gitlab4j/api/merge-request.json

@@ -25,5 +25,10 @@
         "name":"Administrator",
         "state":"active",
         "created_at":"2012-04-29T08:46:00Z"
+    },
+    "diff_refs": {
+        "base_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00",
+        "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
+        "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
     }
 }