[BUG]

[maxbriel]

Describe the bug
Missing a / after the MODELS_PATH makes it impossible to use the CMD package.

To Reproduce
Steps to reproduce the behavior:

1. from hoki.load import set_models_path
2. set_models_path("path/to/models")
3. reload kernel
4. `from hoki.cmd import CMD
5. mycmd = CMD(input_file)
6. run mycmd.make(mag_filter='V', col_filters=['B', 'V'])

Expected behavior
Code generates a CMD and runs for a long duration. Code does should not terminate in a few seconds.

Additional context
Might be impacting other areas too.

Fix should be done when setting the MODELS_PATH. The current assert os.path.isdir() does not catch a missing / at the end of the path.