Add forecast tutorial - #1193

  1 files  ±0    1 suites  ±0   5m 49s ⏱️ -29s
896 tests ±0  892 ✅ ±0  4 💤 ±0  0 ❌ ±0 
907 runs  ±0  903 ✅ ±0  4 💤 ±0  0 ❌ ±0 

Results for commit 458d672. ± Comparison against earlier commit 7a8d3dd.