Add TROUBLESHOOTING section (#36)

README.md

@@ -190,6 +190,11 @@ While the aforementioned example should work for training, we leverage the
 cocoApi for computing the accuracies during testing. Thus, test datasets
 should currently follow the cocoApi for now.
 
+## Troubleshooting
+If you have issues running or compiling this code, we have compiled a list of common issues in
+[TROUBLESHOOTING.md](TROUBLESHOOTING.md). If your issue is not present there, please feel
+free to open a new issue.
+
 ## License
 
 maskrcnn-benchmark is released under the MIT license. See [LICENSE](LICENSE) for additional details.

TROUBLESHOOTING.md

+# Troubleshooting
+
+Here is a compilation if common issues that you might face
+while compiling / running this code:
+
+## Compilation errors when compiling the library
+If you encounter build errors like the following:
+```
+/usr/include/c++/6/type_traits:1558:8: note: provided for ‘template<class _From, class _To> struct std::is_convertible’
+     struct is_convertible
+        ^~~~~~~~~~~~~~
+/usr/include/c++/6/tuple:502:1: error: body of constexpr function ‘static constexpr bool std::_TC<<anonymous>, _Elements>::_NonNestedTuple() [with _SrcTuple = std::tuple<at::Tensor, at::Tensor, at::Tensor, at::Tensor>&&; bool <anonymous> = true; _Elements = {at::Tensor, at::Tensor, at::Tensor, at::Tensor}]’ not a return-statement
+     }
+ ^
+error: command '/usr/local/cuda/bin/nvcc' failed with exit status 1
+```
+check your CUDA version and your `gcc` version.
+```
+nvcc --version
+gcc --version
+```
+If you are using CUDA 9.0 and gcc 6.4.0, then refer to https://github.com/facebookresearch/maskrcnn-benchmark/issues/25,
+which has a summary of the solution. Basically, CUDA 9.0 is not compatible with gcc 6.4.0.
+
+## ImportError: No module named maskrcnn_benchmark.config when running webcam.py
+
+This means that `maskrcnn-benchmark` has not been properly installed.
+Refer to https://github.com/facebookresearch/maskrcnn-benchmark/issues/22 for a few possible issues.
+Note that we now support Python 2 as well.