Merge branch 'gem5_instructions' into 'develop'

Add instructions for the new gem5 integration

See merge request ems/astdm/modeling.dram/dram.sys.5!23

README.md

@@ -69,8 +69,6 @@ To include **DRAMPower** in your build enable the CMake option `DRAMSYS_WITH_DRA
 
 To build DRAMSys on Windows 10 we recommend to use the **Windows Subsystem for Linux (WSL)**.
 
-Information on how to couple DRAMSys with **gem5** can be found [here](DRAMSys/gem5/README.md). 
-
 ### Executing DRAMSys
 
 From the build directory use the commands below to execute the DRAMSys standalone.
@@ -96,6 +94,10 @@ $ ./DRAMSys ../../tests/tests_regression/DDR3/ddr3-example.json ../../tests/test
 
 More information on the configuration can be found [here](configs/README.md).
 
+## gem5 Coupling
+There are two ways to couple DRAMSys with **gem5**:
+- Use the official integration of DRAMSys in gem5. More information can be found in `ext/dramsys` of the gem5 repository.
+- (Deprecated) Compile gem5 as a shared library and link it with DRAMSys, which is only supported in older versions of DRAMSys (tag v4.0).
 
 ## Acknowledgements