Add basic status model

[jacobbieker]

Pull Request

Description

Relates to https://github.com/openclimatefix/nowcasting_api/issues/106 creating the datamodel for status' and reading the latest status from the database

Fixes #

How Has This Been Tested?

Unit test

• [x] Yes

Checklist:

• [x] My code follows OCF's coding style guidelines
• [x] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have checked my code and corrected any misspellings

[codecov-commenter]

Codecov Report

Merging #55 (24bbf1a) into main (3fe8ed6) will decrease coverage by 0.86%. The diff coverage is 64.70%.

@@            Coverage Diff             @@
##             main      #55      +/-   ##
==========================================
- Coverage   98.44%   97.58%   -0.87%     
==========================================
  Files          16       16              
  Lines         645      662      +17     
==========================================
+ Hits          635      646      +11     
- Misses         10       16       +6     

Impacted Files	Coverage Δ
nowcasting_datamodel/models/models.py	94.44% <64.70%> (-5.56%)	:arrow_down:

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[peterdudfield]

We'll have to make some 'migrations' for this too.

I think i'm the only one who can do this for the moment. https://github.com/openclimatefix/nowcasting_datamodel/issues/57