PageCreate can create .txt file but treats it like a .md file

Describe in one or two sentences why you’re opening this issue:

I’m new to JekyllAdmin and had no idea that Create New Page should be used to create only markdown documents. Moreover the plugin did not stop me from creating a .txt file.

Tell us a bit about yourself

• Version of JekyllAdmin I’m using <hint: use bundle show to check>: 0.1.0
• Version of Jekyll I’m using <hint: use bundle show to check>: 3.2.1
• Operating System <e.g. OS X, Windows>: Windows 7
• Browser <e.g, Safari, Chrome>: Chrome

Steps to reproduce

Navigate to http://localhost:3000/admin/page/new create demo.txt by entering that in the breadcrumb Navigate up one level to http://localhost:3000/admin/page

Expected

Expected demo.txt to not be listed there. Expected demo.txt to be listed at /staticfiles.

Actual

demo.txt is listed at /pages

Other details

• There is no clear indication that tells a user, that this interface is to be used only for creating markdown pages nor any validation if he tries to create a .txt file or .html file.
• demo.txt created above has the frontmatter dashes inserted.

[mertkahyaoglu]

Closed via #307

[mertkahyaoglu]

@ashmaroli Just tested this and I think this is half-way fixed in v0.2.0. Creating a file with .txt extension does not result in pages view. The files are created but listed in nowhere. The reason is a wild txt file with front matter :trollface: