commit(mutationKey, payload) {
        let self = this;
        
        // Run a quick check to see if this mutation actually exists
        // before trying to run it
        if(typeof self.mutations[mutationKey] !== 'function') {
            console.log(`Mutation "${mutationKey}" doesn't exist`);
            return false;
        }
        
        // Let anything that's watching the status know that we're mutating state
        self.status = 'mutation';
        
        // Get a new version of the state by running the mutation and storing the result of it
        let newState = self.mutations[mutationKey](self.state, payload);
        
        // Merge the old and new together to create a new state and set it
        self.state = Object.assign(self.state, newState);

        return true;
    }
Look for a mutation and modify the state object 
if that mutation exists by calling it

@param {string} mutationKey
@param {mixed} payload
@returns {boolean}
@memberof Store