Step 2: Add BUILDING document.

BUILDING

+Build instructions for RocketMQ
+
+====================================================
+
+(1) Requisites
+
+JDK 1.7+ is required in order to compile and run RocketMQ.
+
+RocketMQ utilizes Maven as a distribution management and packaging tool. Version 3.0.3 or later is required.
+Maven installation and configuration instructions can be found here:
+
+http://maven.apache.org/run-maven/index.html
+
+
+(2) Executing test cases
+
+Execute the following command in order to compile and test the components:
+
+$ mvn test
+
+
+(3) Importing projects to eclipse
+
+First, generate eclipse project files:
+
+$ mvn -U eclipse:eclipse
+
+Then, import to eclipse by specifying the root directory of the project via:
+
+[File] > [Import] > [Existing Projects into Workspace].
+
+
+(4) Building packages
+
+Execute the following command in order to build the tar.gz packages and install them to the local repository:
+
+$ mvn clean package install assembly:assembly -U
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