Add docs for package command

spacy/__main__.py

@@ -62,7 +62,7 @@ class CLI(object):
     @plac.annotations(
         input_dir=("directory with model data", "positional", None, str),
         output_dir=("output directory", "positional", None, str),
-        force=("force overwriting of existing output directory", "flag", "f", bool)
+        force=("force overwriting of existing folder in output directory", "flag", "f", bool)
     )
     def package(self, input_dir, output_dir, force=False):
         """

website/docs/usage/cli.jade

@@ -103,3 +103,40 @@ p
         +cell #[code --help], #[code -h]
         +cell flag
         +cell Show help message and available arguments.
+
++h(2, "package") Package
+    +tag experimental
+
+p
+    |  Generate a #[+a("/docs/usage/models#own-models") model Python package]
+    |  from an existing model data directory. All data files are copied over,
+    |  and the meta data can be entered directly from the command line. While
+    |  this feature is still experimental, the templates for the
+    |  #[+src(gh("spacy-dev-resources", "templates/model/setup.py")) setup.py] and
+    |  #[+src(gh("spacy-dev-resources", "templates/model/en_morel_name/__init__.py")) __init__.py]
+    |  are downloaded from GitHub. This means you need to be connected to the
+    |  internet to use this command.
+
++code(false, "bash").
+    python -m spacy package [input_dir] [output_dir] [--force]
+
++table(["Argument", "Type", "Description"])
+    +row
+        +cell #[code input_dir]
+        +cell positional
+        +cell Path to directory containing model data.
+
+    +row
+        +cell #[code output_dir]
+        +cell positional
+        +cell Directory to create package folder in.
+
+    +row
+        +cell #[code --force], #[code -f]
+        +cell flag
+        +cell Force overwriting of existing folder in output directory.
+
+    +row
+        +cell #[code --help], #[code -h]
+        +cell flag
+        +cell Show help message and available arguments.