Function Modifiers
Modifiers are functions that wrap other functions. They have a special function they can run _;
which means that the next function should run, but this special function can appear in the middle of a modifier's function. There can also be many modifiers attached to a function.
We can either write modifiers as functions, or we can unwrap the modifiers and make them part of the function.
Solidity Link: https://solidity.readthedocs.io/en/v0.4.24/contracts.html#function-modifiers
Related Issues: #4 (closed) #18 (closed)
Edited by Jon Shahen