Added Tag and Release models

src/main/java/org/gitlab/api/models/GitlabRelease.java

+package org.gitlab.api.models;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class GitlabRelease {
+
+    @JsonProperty("tag_name")
+    private String tagName;
+
+    @JsonProperty("description")
+    private String description;
+
+    public String getTagName() {
+        return tagName;
+    }
+
+    public void setTagName(String tagName) {
+        this.tagName = tagName;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

src/main/java/org/gitlab/api/models/GitlabTag.java

+package org.gitlab.api.models;
+
+import org.gitlab.api.models.GitlabBranchCommit;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class GitlabTag {
+
+    public final static String URL = "/repository/tags/";
+
+    @JsonProperty("commit")
+    private GitlabBranchCommit commit;
+
+    @JsonProperty("release")
+    private GitlabRelease release;
+
+    @JsonProperty("name")
+    private String name;
+
+    @JsonProperty("message")
+    private String message;
+
+    public GitlabBranchCommit getCommit() {
+        return commit;
+    }
+
+    public void setCommit(GitlabBranchCommit commit) {
+        this.commit = commit;
+    }
+
+    public GitlabRelease getRelease() {
+        return release;
+    }
+
+    public void setRelease(GitlabRelease release) {
+        this.release = release;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}