Create CONTRIBUTING.md
Create CONTRIBUTING.md

lettuce-io/lettuce-core,taer/lettuce,pulse00/lettuce,lettuce-io/lettuce-core,pulse00/lettuce,lettuce-io/lettuce-core,Hocdoc/lettuce,Hocdoc/lettuce,taer/lettuce,lettuce-io/lettuce-core,mp911de/lettuce,mp911de/lettuce