Rail Integration

[JaimeRZP]

WIP

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 61.11111% with 14 lines in your changes missing coverage. Please review.

Project coverage is 98.1%. Comparing base (a6c217a) to head (d7363cc).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #441 +/- ## ======================================== - Coverage 98.5% 98.1% -0.4% ======================================== Files 48 48 Lines 3667 3688 +21 ======================================== + Hits 3612 3619 +7 - Misses 55 69 +14 ``` | [Files](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/441?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC) | Coverage Δ | | |---|---|---| | [firecrown/likelihood/number\_counts.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/441?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fnumber_counts.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2QvbnVtYmVyX2NvdW50cy5weQ==) | `90.8% <100.0%> (-0.3%)` | :arrow_down: | | [firecrown/likelihood/weak\_lensing.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/441?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fweak_lensing.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2Qvd2Vha19sZW5zaW5nLnB5) | `96.1% <100.0%> (-0.2%)` | :arrow_down: | | [firecrown/likelihood/source.py](https://app.codecov.io/gh/LSSTDESC/firecrown/pull/441?src=pr&el=tree&filepath=firecrown%2Flikelihood%2Fsource.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=LSSTDESC#diff-ZmlyZWNyb3duL2xpa2VsaWhvb2Qvc291cmNlLnB5) | `90.7% <58.8%> (-9.3%)` | :arrow_down: |