Can't get generated xcode project to compile

To test xchammer I tried the workflow on the _Tailor_ sample code. I did the following:

```
cd sample/Tailor
xchammer generate XCHammer.yaml
```

And the output was the following
```
ERROR: /Users/William/Documents/work/clients/perceptolab/research/xchammer/sample/Tailor/BUILD:8:1: in ios_application rule //:ios-app:
Traceback (most recent call last):
File "/Users/William/Documents/work/clients/perceptolab/research/xchammer/sample/Tailor/BUILD", line 8
ios_application(name = 'ios-app')
File "/private/var/tmp/_bazel_William/bc9f6e1936ebc1d1d725c6dd8e3ade19/external/build_bazel_rules_apple/apple/internal/ios_rules.bzl", line 160, in _ios_application_impl
run_support.register_simulator_executable(<2 more arguments>)
File "/private/var/tmp/_bazel_William/bc9f6e1936ebc1d1d725c6dd8e3ade19/external/build_bazel_rules_apple/apple/internal/run_support.bzl", line 28, in run_support.register_simulator_executable
ctx.actions.expand_template(<4 more arguments>)
File "/private/var/tmp/_bazel_William/bc9f6e1936ebc1d1d725c6dd8e3ade19/external/build_bazel_rules_apple/apple/internal/run_support.bzl", line 36, in ctx.actions.expand_template
shell.quote(<1 more arguments>)
File "/private/var/tmp/_bazel_William/bc9f6e1936ebc1d1d725c6dd8e3ade19/external/bazel_skylib/lib/shell.bzl", line 49, in shell.quote
s.replace("'", "'\\''")
type 'NoneType' has no method replace()```

To mitigate this I changed the rules_apple.git repository tag to 0.19.0. At this point the project is generated but it won't compile.
XCode output is the following:

```
:0: error: module map file 'tulsi-workspace/bazel-tulsi-includes/x/x/tailor.modulemaps/module.modulemap' not found
:0: error: module map file 'tulsi-workspace/bazel-tulsi-includes/x/x/tailor.modulemaps/module.modulemap' not found
:0: error: missing required module 'SwiftShims'
```

I'm using bazel 2.0.0

Thank you!