Implemented login & added tests

scm-webapp/src/main/java/sonia/scm/api/v2/resources/MeResource.java

@@ -0,0 +1,34 @@
+package sonia.scm.api.v2.resources;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.apache.shiro.SecurityUtils;
+import sonia.scm.web.VndMediaType;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.Response;
+
+@Path(MeResource.ME_PATH_V2)
+public class MeResource {
+  static final String ME_PATH_V2 = "v2/me/";
+
+  @GET
+  @Produces(VndMediaType.ME)
+  public Response get() {
+    MeDto meDto = new MeDto((String) SecurityUtils.getSubject().getPrincipals().getPrimaryPrincipal());
+    return Response.ok(meDto).build();
+  }
+
+  @NoArgsConstructor
+  @AllArgsConstructor
+  @Getter
+  @Setter
+  class MeDto {
+    String username;
+  }
+
+}