Update schema and alembic so we only have unique metric names

[hamishteagle]

We previously had a situation where some of the metric names in metric table were duplicated, this leads to errors when running the insight bot as we perform lookups for the id based on the name. This adds the condition that the name must be unique.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.8%. Comparing base (4a7e731) to head (4acce6b).

Additional details and impacted files

[](https://app.codecov.io/gh/synthesized-io/insight/pull/185?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=synthesized-io) ```diff @@ Coverage Diff @@ ## master #185 +/- ## ====================================== Coverage 78.8% 78.8% ====================================== Files 11 11 Lines 971 971 Branches 160 160 ====================================== Hits 766 766 Misses 153 153 Partials 52 52 ``` | [Files](https://app.codecov.io/gh/synthesized-io/insight/pull/185?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=synthesized-io) | Coverage Δ | | |---|---|---| | [src/insight/database/schema.py](https://app.codecov.io/gh/synthesized-io/insight/pull/185?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=synthesized-io#diff-c3JjL2luc2lnaHQvZGF0YWJhc2Uvc2NoZW1hLnB5) | `100.0% <100.0%> (ø)` | |

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud